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Dolphin Speed and Specification


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#81 WWBrian

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Posted 24 May 2011 - 01:38

I suppose then, they simply were removed out of sheer hazard…

…I can imagine them being extremely useful though, not for the obvious flying under a 2-seater and shooting upwards…but more importantly, when not-being-quite-able to keep a turn to bring your Vickers to bare on to your opponent….you could just get not-quite-as-sharp of a turn and use your fixed Lewis guns instead.

Seems pretty useful to me. Guess that's just one more difference bewteen a combat sim and real life eh'?

Thanks for the discussion fellas.
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#82 gavagai

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Posted 24 May 2011 - 13:43

If this hasn't been posted before (from Profile Publications, JM Bruce):

Attached File  dolphinperformance.PNG   463.26KB   384 downloads

Our Dolphin's airspeed is actually better than the third column under the Mk.I (Lang 3610 prop), but ours doesn't climb as well at low altitude. The climb times to 10,000ft are closer, however.

If our Dolphin is supposed to have the Lang 3800 prop, then it is indeed too slow at 10,000ft.
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#83 MiG-77

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Posted 24 May 2011 - 14:08

If this hasn't been posted before (from Profile Publications, JM Bruce):

It has been posted before.

Our Dolphin's airspeed is actually better than the third column under the Mk.I (Lang 3610 prop), but ours doesn't climb as well at low altitude. The climb times to 10,000ft are closer, however.

If our Dolphin is supposed to have the Lang 3800 prop, then it is indeed too slow at 10,000ft.

Lang 3610 prop was "standard" and I think that is what RoF Dolphin is supposed to be. Also test with Lang 3800 has 59lb lighter weight.
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#84 gavagai

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Posted 24 May 2011 - 14:19

So then our Dolphin airspeed is not too slow, but its climb is a bit slow to 2km.
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#85 MiG-77

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Posted 24 May 2011 - 14:33

So then our Dolphin airspeed is not too slow, but its climb is a bit slow to 2km.

Well, IMHO it is little too slow also, but nothing to cry a river (Compared to some other planes) ;)
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#86 gavagai

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Posted 24 May 2011 - 14:35

Attached File  TASmphft.PNG   86.85KB   348 downloads

119.5mph at 10,000ft? Ours is faster. Unlike the other Sopwith crates, it seem the Dolphin is the only one in the family to suffer an airspeed penalty because of its giant wings (relative to its power). :lol:
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#87 MiG-77

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Posted 24 May 2011 - 14:40

119.5mph at 10,000ft? Ours is faster. Unlike the other Sopwith crates, it seem the Dolphin is the only one in the family to suffer an airspeed penalty because of its giant wings (relative to its power). :lol:

It is quite close at 10 000ft, but I dont think it is at sealevel. Better climb time also suggest that it might have more power at lower altitude.
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#88 Heliocon

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Posted 05 June 2011 - 17:30

After some more flying my feeling is that the dolphin isnt a unusually bad plane, it just sucks at the current MP servers because the air combat is all under 3000ft normally and the plane is mediocre with everything else. I think the dolphin would be/is a good zoom and boom plane because the frame seems to be able to take very high speed dives, unfortunetly it has some major drawbacks like the fact that its power/climb rate feels to low/slow, once you lose the dive speed your stuffed because many other planes can catch up to you and or outclimb you. In a dogfight especially at 1500 or lower where it doesnt have a dive advantage, because of the horrible stall and spin problems the plane is a death trap. Its a slow turner, even when maxed out and if you are careful / play it safe about the stalls its one of the slowest turning planes I have flown.
Its climb also sucks like said which makes holding altitude while dogfighting very difficult, I have to lose altitude in a fight not to death stall, where as in other planes I could choose to semi disengage and circle from overhead because I dont have to dive to evade being shot. The huge wingspan in this case just doesnt give the plane the lift I would think it should have (maybe because its heavier, but wood and fabric is still alot lighter then steel) or the pure power that would come from being heavier but having a high HP engine.
One other weird thing is the DVIIF performance vs the Dolphin at high altitude - the DVIIF is faster at 5000m…? That doesnt make sense to me (maybe I am missing something), also the dolphin looks alot more streamlined so considering it has the same HP as the SE5A why does it have a lower top speed? If anything it should be higher because it wont fall apart in a high G turn at speed like the SE5A does (wings rip off).
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#89 MattM

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Posted 05 June 2011 - 19:15

One other weird thing is the DVIIF performance vs the Dolphin at high altitude - the DVIIF is faster at 5000m…? That doesnt make sense to me (maybe I am missing something), also the dolphin looks alot more streamlined so considering it has the same HP as the SE5A why does it have a lower top speed? If anything it should be higher because it wont fall apart in a high G turn at speed like the SE5A does (wings rip off).
If there's any altitude the D.VIIF should definately be faster, it's 5000 meters up. The BMW engine was suited for higher altitudes. Also the D.VII is a less draggy plane compared to the Dolphin, so even if both planes would've had the same engine, the D.VII would still be faster. The rigging wires of the Dolphin, together with the two-bay construction, should easily cause more drag.

The SE5a is a single-bay construction with less wing-area and wayyy less wingspan. I really don't see a way the Dolphin could've been less draggy than the SE5a. But it's complicated to compare those two planes, because they don't have the same engine nor propeller.

The Dolphin was probably a bit faster at low altitudes and climbed a bit faster than it currently does. I really like the Dolphin, but many other planes need more attention imho.
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#90 Heliocon

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Posted 07 June 2011 - 05:46

One other weird thing is the DVIIF performance vs the Dolphin at high altitude - the DVIIF is faster at 5000m…? That doesnt make sense to me (maybe I am missing something), also the dolphin looks alot more streamlined so considering it has the same HP as the SE5A why does it have a lower top speed? If anything it should be higher because it wont fall apart in a high G turn at speed like the SE5A does (wings rip off).
If there's any altitude the D.VIIF should definately be faster, it's 5000 meters up. The BMW engine was suited for higher altitudes. Also the D.VII is a less draggy plane compared to the Dolphin, so even if both planes would've had the same engine, the D.VII would still be faster. The rigging wires of the Dolphin, together with the two-bay construction, should easily cause more drag.

The SE5a is a single-bay construction with less wing-area and wayyy less wingspan. I really don't see a way the Dolphin could've been less draggy than the SE5a. But it's complicated to compare those two planes, because they don't have the same engine nor propeller.

The Dolphin was probably a bit faster at low altitudes and climbed a bit faster than it currently does. I really like the Dolphin, but many other planes need more attention imho.

Ok I dont know about the engine but when I look at the planes the D.VIIF's frame (blocky front is not aerodynamic) looks no where as streamlined as the dolphin (curved and compact) which has more wing surface (= more climb?…) but a lower profile (low top wing) which counteracts atleast some of the added weight. Now the SE5a is alot lighter then the dolphin so I could see it climbing alot faster, but there is no way it has a lower top speed. The dolpin is significantly heavier, so while it does has a larger wing surface, it would reach a higher speed in a dive because we are talking about approaching terminal velocity and in this case weight outweights (no pun intended) a larger wing span, which just rips off in any case in a equivalent speed dive. - If the dolphin was made for high altitude combat that means a high top speed (less air = less lift so you need more speed) and a plane with the ability to dive into the enemy from height, which again means a higher dive + max speed then what we currently have imo.
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#91 WWBrian

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Posted 07 June 2011 - 06:54

More Dolphin data (Mk II variant?)

…but Bulletin reference at bottom provides clues on further research information.

Attached Files


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#92 MiG-77

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Posted 07 June 2011 - 07:03

More Dolphin data (Mk II variant?)

…but Bulletin reference at bottom provides clues on further research information.

Yep, it is Dolphin II data so not important for RoF plane.
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#93 WWBrian

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Posted 07 June 2011 - 07:07

yeah, but thought it interesting for two reasons….makes me want to look up the STAe bulletin #7 to see what else is listed….and also as wishfull thinking since they can put a BMW in the P12…well….heh… :mrgreen:
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#94 MiG-77

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Posted 07 June 2011 - 07:14

Ok I dont know about the engine but when I look at the planes the D.VIIF's frame (blocky front is not aerodynamic) looks no where as streamlined as the dolphin (curved and compact) which has more wing surface (= more climb?…) but a lower profile (low top wing) which counteracts atleast some of the added weight.

Just looking cowling is very misleading. D.VII didnt have wires that caused huge drag and also it was smaller (less frontal area -> less drag). Also D.VII wingprofile was one of the most efficient wingprofils in WWI (in lift/drag ratio). So D.VII (BMW) was smaller (less total drag) and had better power/weight ratio. So it is easy to see why BMW D.VII could be faster (There are even anecdotes of BMW D.VII outrunning SE5a)


Now the SE5a is alot lighter then the dolphin so I could see it climbing alot faster, but there is no way it has a lower top speed. The dolpin is significantly heavier, so while it does has a larger wing surface, it would reach a higher speed in a dive because we are talking about approaching terminal velocity and in this case weight outweights (no pun intended) a larger wing span, which just rips off in any case in a equivalent speed dive. - If the dolphin was made for high altitude combat that means a high top speed (less air = less lift so you need more speed) and a plane with the ability to dive into the enemy from height, which again means a higher dive + max speed then what we currently have imo.

Weight dont affect max diving speed at all (it is all about thrust/drag), so your conclussions are wrong in there. Second, Dolphin was slower in every altitude compared to SE5a becasue it was draggier.
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#95 ImPeRaToR

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Posted 07 June 2011 - 10:26

I am not too sure about wing area helping with climb, I think it's primarily thrust to weight that helps. Look at the D.VIII, it has less wing area than the Dr.I yet climbs just the same because thrust-to-weight is very very similar.

N17 also climbs well with relatively small wing area.
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#96 MiG-77

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Posted 07 June 2011 - 12:54

I am not too sure about wing area helping with climb, I think it's primarily thrust to weight that helps. Look at the D.VIII, it has less wing area than the Dr.I yet climbs just the same because thrust-to-weight is very very similar.

N17 also climbs well with relatively small wing area.

Yep, thrust/drag ratio is most important (but wings do affect to drag by different amount in different AoAs -> thick wing like D.VII is partically good at high AoA sitatuations by generating less drag than thin wing -> "helps" to climb better).
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#97 Heliocon

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Posted 07 June 2011 - 13:15

Ok I dont know about the engine but when I look at the planes the D.VIIF's frame (blocky front is not aerodynamic) looks no where as streamlined as the dolphin (curved and compact) which has more wing surface (= more climb?…) but a lower profile (low top wing) which counteracts atleast some of the added weight.

Just looking cowling is very misleading. D.VII didnt have wires that caused huge drag and also it was smaller (less frontal area -> less drag). Also D.VII wingprofile was one of the most efficient wingprofils in WWI (in lift/drag ratio). So D.VII (BMW) was smaller (less total drag) and had better power/weight ratio. So it is easy to see why BMW D.VII could be faster (There are even anecdotes of BMW D.VII outrunning SE5a)


Now the SE5a is alot lighter then the dolphin so I could see it climbing alot faster, but there is no way it has a lower top speed. The dolpin is significantly heavier, so while it does has a larger wing surface, it would reach a higher speed in a dive because we are talking about approaching terminal velocity and in this case weight outweights (no pun intended) a larger wing span, which just rips off in any case in a equivalent speed dive. - If the dolphin was made for high altitude combat that means a high top speed (less air = less lift so you need more speed) and a plane with the ability to dive into the enemy from height, which again means a higher dive + max speed then what we currently have imo.

Weight dont affect max diving speed at all (it is all about thrust/drag), so your conclussions are wrong in there. Second, Dolphin was slower in every altitude compared to SE5a becasue it was draggier.

Wait? Basic physics - since we are not in a vacumn, maximum dive speed (terminal velocity) is determined by a mix of weight and in this case drag (density but that doesnt apply here), the SE5a can have less drag, but if it weighs alot less then the dolphin its max dive speed will be lower, so its a question of drag vs weight here and if its diving a front profile produces the least amount of drag. Remember engine power is not counted.

Also wing size DOES increase climb rate proportionally (more wing surface at the same rate = more lift, but not always more efficiency).
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#98 Tom-Cundall

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Posted 07 June 2011 - 13:25

Trouble is with aircraft that as you gain speed in a dive you also gain lift (trying to force the nos back up) as the airflow speeds up across the wings (think about it) - this is what reportedly made the DR1 quite difficult to 'force' to dive steeply/sustatined.
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#99 Heliocon

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Posted 07 June 2011 - 13:30

I am not too sure about wing area helping with climb, I think it's primarily thrust to weight that helps. Look at the D.VIII, it has less wing area than the Dr.I yet climbs just the same because thrust-to-weight is very very similar.

N17 also climbs well with relatively small wing area.

Yep, thrust/drag ratio is most important (but wings do affect to drag by different amount in different AoAs -> thick wing like D.VII is partically good at high AoA sitatuations by generating less drag than thin wing -> "helps" to climb better).

You just contradicted what he said. Note he said "Thrust to Weight" and you said "thrust/drag" which are two completely different things. Both are important, in a climb the factors are - HP(thrust), Weight, Drag. Now thrust and drag may make a big differance in a climb rate, but little differance in a dive because in a dive the most important factors are weight and drag since you will dive until terminal velocity, thrust is no longer a factor. Now while all objects fall at the same speed in a vacumn, when you dive there is air resistance (drag) which counter acts weight (for a sphere you would just use density as a lead ball of the same dimensions as styrafoam falls alot faster) and you reach an equilibrium. In this case the drag is minimal between different plane models while the weight can be very different, which means weight would win out.

Also remember the dolphin has the thicker wing than the SE5A because the dolphin is high alt fighter, also the SE5A wing COULD NOT take a very high speed dive as it would rip its wings off… please address this problem (would not happen to dolphin).

@Tom - yep, I dont know exactly when it happens but there are some exceptions to this. I know in WW2 a guy was nearly killed because he dived after an enemy fighter from very high alt, his speed approached the sound barrier and the pressure from the airflow made all control surfaces innoperable (not physically strong enough to move them against the massive pressure from airflow). Eventually he managed to pull out though.
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#100 MiG-77

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Posted 07 June 2011 - 13:55

Wait? Basic physics - since we are not in a vacumn, maximum dive speed (terminal velocity) is determined by a mix of weight and in this case drag (density but that doesnt apply here), the SE5a can have less drag, but if it weighs alot less then the dolphin its max dive speed will be lower, so its a question of drag vs weight here and if its diving a front profile produces the least amount of drag. Remember engine power is not counted.

Basic physics is that weight dont affect object velocity/acceleration. -> In vacuum all sized/weighted object fall same speed as different drag is eliminated.

Also wing size DOES increase climb rate proportionally (more wing surface at the same rate = more lift, but not always more efficiency).

No it does not. Best "climbers" are rockets and they dont ahve wings at all… :D
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#101 ImPeRaToR

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Posted 07 June 2011 - 14:10

Also remember the dolphin has the thicker wing than the SE5A because the dolphin is high alt fighter, also the SE5A wing COULD NOT take a very high speed dive as it would rip its wings off… please address this problem (would not happen to dolphin).

Feel free to elaborate and supply some proof. :)
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#102 Heliocon

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Posted 07 June 2011 - 21:21

Wait? Basic physics - since we are not in a vacumn, maximum dive speed (terminal velocity) is determined by a mix of weight and in this case drag (density but that doesnt apply here), the SE5a can have less drag, but if it weighs alot less then the dolphin its max dive speed will be lower, so its a question of drag vs weight here and if its diving a front profile produces the least amount of drag. Remember engine power is not counted.

Basic physics is that weight dont affect object velocity/acceleration. -> In vacuum all sized/weighted object fall same speed as different drag is eliminated.

Also wing size DOES increase climb rate proportionally (more wing surface at the same rate = more lift, but not always more efficiency).

No it does not. Best "climbers" are rockets and they dont ahve wings at all… :D

I quote myself "since we are not in a vacumn" was the first thing I said, as for proof I dont have any, I am just thinking about the numbers/airframes and it doesnt seem to make sense… granted an se5 could have a faster dive rate but the question is again, can the airfram/wings survive it?

As for rockets - wrong time period, I mean seriously dude your rocket booster vs my motorcycle engine in a reinforced shipping crate frame, kept aloft by paper-mache and toothpick wings stuck on with bubble gum is not a fair comparison.
-First I have to buy these new gizmos with lots of numbers, that are rotated 90 degrees sideways and when you finally can make out a word you find out its in french thingy mabob things… then we can compare rides… ok? OK???
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#103 MiG-77

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Posted 08 June 2011 - 13:39

I quote myself "since we are not in a vacumn" was the first thing I said, as for proof I dont have any, I am just thinking about the numbers/airframes and it doesnt seem to make sense… granted an se5 could have a faster dive rate but the question is again, can the airfram/wings survive it?

Vacuum just proves that "weight" has nothing to do with max speed (objects still weight differently in vacuum). Just drag and density that affects to air resistance. Also as have beed said SE5a was one of the fastest divers in WWI, Dolphing was not. Also have you even looked how much weight difference between the two planes had?

As for rockets - wrong time period, I mean seriously dude your rocket booster vs my motorcycle engine in a reinforced shipping crate frame, kept aloft by paper-mache and toothpick wings stuck on with bubble gum is not a fair comparison.
-First I have to buy these new gizmos with lots of numbers, that are rotated 90 degrees sideways and when you finally can make out a word you find out its in french thingy mabob things… then we can compare rides… ok? OK???


Again rocket example just proves that "wings" has nothing/very little to do with maximum climb (In rocket case "wings" would just slower it down).
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#104 Heliocon

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Posted 08 June 2011 - 16:49

I quote myself "since we are not in a vacumn" was the first thing I said, as for proof I dont have any, I am just thinking about the numbers/airframes and it doesnt seem to make sense… granted an se5 could have a faster dive rate but the question is again, can the airfram/wings survive it?

Vacuum just proves that "weight" has nothing to do with max speed (objects still weight differently in vacuum). Just drag and density that affects to air resistance. Also as have beed said SE5a was one of the fastest divers in WWI, Dolphing was not. Also have you even looked how much weight difference between the two planes had?

As for rockets - wrong time period, I mean seriously dude your rocket booster vs my motorcycle engine in a reinforced shipping crate frame, kept aloft by paper-mache and toothpick wings stuck on with bubble gum is not a fair comparison.
-First I have to buy these new gizmos with lots of numbers, that are rotated 90 degrees sideways and when you finally can make out a word you find out its in french thingy mabob things… then we can compare rides… ok? OK???


Again rocket example just proves that "wings" has nothing/very little to do with maximum climb (In rocket case "wings" would just slower it down).

Ok I have to say the above post is incredibly stupid, but I will try to explain this to you.
1. Weight makes a differance when NOT in a vacumn, guess why? Density = weight/volume. Heavier objects fall faster, when not in a vacumn because in a vacumn there is NO air resistance and a gravitational equation is used, but if there is air we need to calculate the amount of resistance on the objects surface area. This is calculated by desnity, but since you cant use density for a plane in a dive you need to calculate drag, because density in a plane has different values depending on area and non-uniform dimensions.

Your comment on rockets makes me face palm, why not just strip the wings off your plane and point it up? Thats what you are basically suggesting here. Rockets DO NOT USE LIFT to gain altitude. They simply use chemicle -> kinetic energy to accelerate without generating any lift. A plane does the same thing but has far less kinetic energy and therefore needs wings to generate lift, which is generated by airflowing over a wing. Also remember that since a rocket is going into LEO generally where the air density is low - none, wings dont really help do they?
This is like elementary physics, I am not even arguing anymore about plane specs because if you dont know how A affects B there is not point in debating anything (which I may well be wrong about, but if you dont know aerodynamics you are equally wrong).
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#105 MiG-77

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Posted 08 June 2011 - 18:00

Ok I have to say the above post is incredibly stupid, but I will try to explain this to you.
1. Weight makes a differance when NOT in a vacumn, guess why? Density = weight/volume. Heavier objects fall faster, when not in a vacumn because in a vacumn there is NO air resistance and a gravitational equation is used, but if there is air we need to calculate the amount of resistance on the objects surface area. This is calculated by desnity, but since you cant use density for a plane in a dive you need to calculate drag, because density in a plane has different values depending on area and non-uniform dimensions.

"Weight" in free fall is just gravitanional force which is pulls objects in same speed. -> weight dont affect speed, density does (Density is not same as weight). So your claim that weight affect speed is wrong. Density and drag does. Also go and look weight difference of SE5a and Dolphin and then compare their size.


Your comment on rockets makes me face palm, why not just strip the wings off your plane and point it up? Thats what you are basically suggesting here. Rockets DO NOT USE LIFT to gain altitude. They simply use chemicle -> kinetic energy to accelerate without generating any lift. A plane does the same thing but has far less kinetic energy and therefore needs wings to generate lift, which is generated by airflowing over a wing. Also remember that since a rocket is going into LEO generally where the air density is low - none, wings dont really help do they?
This is like elementary physics, I am not even arguing anymore about plane specs because if you dont know how A affects B there is not point in debating anything (which I may well be wrong about, but if you dont know aerodynamics you are equally wrong).

Rockets use thrust/weight and that why I say it is most important even in planes. What you dont seem to grasp is that lift always causes drag and when climbing drag is bad. Also in climbing, lift vector get worse and worse as AoA increases. Now really, go look planes historical data. Planes that had relatively small wing area had very good climb rate (Nieuports, D.VIIF, D.VIII). What is common on all good climbing planes is their good thrust/weight ratio. Wingarea is mostly irrelevant.
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#106 Heliocon

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Posted 09 June 2011 - 03:08

Ok I have to say the above post is incredibly stupid, but I will try to explain this to you.
1. Weight makes a differance when NOT in a vacumn, guess why? Density = weight/volume. Heavier objects fall faster, when not in a vacumn because in a vacumn there is NO air resistance and a gravitational equation is used, but if there is air we need to calculate the amount of resistance on the objects surface area. This is calculated by desnity, but since you cant use density for a plane in a dive you need to calculate drag, because density in a plane has different values depending on area and non-uniform dimensions.

"Weight" in free fall is just gravitanional force which is pulls objects in same speed. -> weight dont affect speed, density does (Density is not same as weight). So your claim that weight affect speed is wrong. Density and drag does. Also go and look weight difference of SE5a and Dolphin and then compare their size.


Your comment on rockets makes me face palm, why not just strip the wings off your plane and point it up? Thats what you are basically suggesting here. Rockets DO NOT USE LIFT to gain altitude. They simply use chemicle -> kinetic energy to accelerate without generating any lift. A plane does the same thing but has far less kinetic energy and therefore needs wings to generate lift, which is generated by airflowing over a wing. Also remember that since a rocket is going into LEO generally where the air density is low - none, wings dont really help do they?
This is like elementary physics, I am not even arguing anymore about plane specs because if you dont know how A affects B there is not point in debating anything (which I may well be wrong about, but if you dont know aerodynamics you are equally wrong).

Rockets use thrust/weight and that why I say it is most important even in planes. What you dont seem to grasp is that lift always causes drag and when climbing drag is bad. Also in climbing, lift vector get worse and worse as AoA increases. Now really, go look planes historical data. Planes that had relatively small wing area had very good climb rate (Nieuports, D.VIIF, D.VIII). What is common on all good climbing planes is their good thrust/weight ratio. Wingarea is mostly irrelevant.

First I want to say sorry about the above post because I edited after I posted it but for some reason the edits did not stick/change.
You are still wrong, density = weight/volume. In my edit I explained this more in detail but you are flat out wrong, its not a debate, go google it. In a vacumn is a different situation, but as I have said more than once here (please read the comments because I am getting tired of repeating them) weight and drag are the factors. This is because a plane's density is not used in the calculations for terminal velocity (it can but its not practical) - this is because a plane is not uniform in dementions (like a sphere) and not uniform in density (weight distribution) and therefore you use drag and weight to calculate terminal velocity instead of weight and volume (=density (density=weight/volume)). If you go to the top of a tower and drop two speheres, each with a 1 foot diameter, but one ball made of styrofoam and the other of lead - the lead will drop ALOT faster. Why? Because its a hell of alot more dense (more weight per area of volume). This is because wind resistance over the balls surface area gives less resistance in proportion to a lighter styrofoam ball. In a vacumn where there is no air this effect is negated and they would fall at the same speed.

Although in actual fact it should be noted that 2 objects dont fall at the same speed in a vacumn because the earth falls towards the objects as the objects fall towards the earth, its just the extreme inbalance of mass makes it seem like they are both falling to a stationary point (the ground).

You may be right about the planes, I never said I knew I just said what I thought from what I had seen in the game etc, but you are flat out wrong/misguided about the basic physics here. Now address this point - if drag is ALWAYS bad and lift causes drag - why not take the wings off your plane? I am sorry but as someone who knows elementary physics your posts are alittle absurd here, like the fact that you dont realise the equation used to determine an objects density. Also lift and drag are different things, although they are both caused by airflow over a surface (lift is directional hence the name lift, while drag is the effect of airflow slowing an object down to generally a still speed).
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#107 Heliocon

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Posted 09 June 2011 - 03:37

Also just for the record - you are right about the thrust and weight ratios making a differance in climb rate to a large degree, but its not to do with the wing size. Why? Because a faster plane needs less wing surface to stay airborn, therefore the faster a plane is compared to its weight the smaller its wings can be, and it can fly faster but not necessarily climb faster, its a balance between the speed generating more lift on a smaller wing vs having more wing and possibly being slower. Too much in either direction doesnt work. You can see this dynamic at work when you compare the SE5A which is fast for its weight to the hadleypage which is slow but uses a large wing surfact to stay aloft.

Anything can move up if it has enough power, like a rocket, but a ww1 does not have enough HP/weight to climb without using wings for lift.
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#108 MiG-77

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Posted 09 June 2011 - 07:57

First I want to say sorry about the above post because I edited after I posted it but for some reason the edits did not stick/change.
You are still wrong, density = weight/volume. In my edit I explained this more in detail but you are flat out wrong, its not a debate, go google it. In a vacumn is a different situation, but as I have said more than once here (please read the comments because I am getting tired of repeating them) weight and drag are the factors. This is because a plane's density is not used in the calculations for terminal velocity (it can but its not practical) - this is because a plane is not uniform in dementions (like a sphere) and not uniform in density (weight distribution) and therefore you use drag and weight to calculate terminal velocity instead of weight and volume (=density (density=weight/volume)). If you go to the top of a tower and drop two speheres, each with a 1 foot diameter, but one ball made of styrofoam and the other of lead - the lead will drop ALOT faster. Why? Because its a hell of alot more dense (more weight per area of volume). This is because wind resistance over the balls surface area gives less resistance in proportion to a lighter styrofoam ball. In a vacumn where there is no air this effect is negated and they would fall at the same speed.

Drop 2 balls where other has larger weight but less density and other has less weight but higher density (IOW Larger heavier ball vs smaller lighter ball). Which one again drops faster? Now both are exact spheres so drag coefficiency is exactly same in both. Again, weight itself has nothing to do with fall speed as now heavier object will fall slower.


Although in actual fact it should be noted that 2 objects dont fall at the same speed in a vacumn because the earth falls towards the objects as the objects fall towards the earth, its just the extreme inbalance of mass makes it seem like they are both falling to a stationary point (the ground).

And this "falling speed" or "gravitional speed" is same to all objects.

You may be right about the planes, I never said I knew I just said what I thought from what I had seen in the game etc, but you are flat out wrong/misguided about the basic physics here. Now address this point - if drag is ALWAYS bad and lift causes drag - why not take the wings off your plane? I am sorry but as someone who knows elementary physics your posts are alittle absurd here, like the fact that you dont realise the equation used to determine an objects density. Also lift and drag are different things, although they are both caused by airflow over a surface (lift is directional hence the name lift, while drag is the effect of airflow slowing an object down to generally a still speed).

IF your only point is to make "plane" climb effectively, you take wings off and just make good thrust/weigth ratio -> IE Rocket.
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#109 Sensenmann

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Posted 09 June 2011 - 07:59

Sorry MiG, but I have to agree with Heliocon here,


A little math problem for you:

F = (G*M1*M2)/R^2

Where

G = 6.67*10^-11

M1 = the mass of the object being dropped (in kilograms)

M2 = 5.97*10^24 kg (mass of the earth)

R = the distance the object is being dropped (in meters), for consistency lets say R is 1000 meters


Plug in any number you want for M1…


Once you have solved for F, plug it into this formula:

A = F/M1

The first formula is for determining the gravitational force being exerted on both the object (M1) and the Earth (M2). The second formula is for determining the rate of acceleration that gravitational force has on the object.

You will find that no matter what number you use for M1, the acceleration (A) is always the same.

Keep in mind Newton's first Law of Motion, where it is stated that "a body at rest tends to stay at rest, and a body in motion (in a straight line) tends to stay in motion". When you drop your object (M1) it starts at a state of rest, and the force of gravity begins to accelerate it. As I have shown you above, irregardless of the mass of M1, the resultant acceleration is always the same.

What this means it that no matter what the mass of the object you are dropping, it always "falls" at the same rate of acceleration (in a vacuum).

If you perform this same experiment in a medium of a given density (such as the atmosphere) the object will meet resistance (drag) due to the physical dimensions of the object moving through that medium.

Terminal velocity is the product of the above gravitational force (F) being balanced by the drag of the object. This holds true for WWI aircraft as well.

When you initiate a dive in, say the SE5a, as you increase speed your prop begins to generate less thrust and more drag. Your terminal velocity is still a product of gravity pulling you down and the resistance of drag (slowing down your rate of descent).


However, in terms of the dive speed of the SE5a vs. the Dolphin, my money is on the SE5a having a higher dive speed. Why? Because it is evident that the SE5a has less surface area which will result in less drag. The SE5a has 99% of the mass of the Dolphin (based on an average of empty and takeoff weights) but is roughly 88% the size of the Dolphin (based on overall dimensions).
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#110 MiG-77

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Posted 09 June 2011 - 08:04

Also just for the record - you are right about the thrust and weight ratios making a differance in climb rate to a large degree, but its not to do with the wing size. Why? Because a faster plane needs less wing surface to stay airborn, therefore the faster a plane is compared to its weight the smaller its wings can be, and it can fly faster but not necessarily climb faster, its a balance between the speed generating more lift on a smaller wing vs having more wing and possibly being slower. Too much in either direction doesnt work. You can see this dynamic at work when you compare the SE5A which is fast for its weight to the hadleypage which is slow but uses a large wing surfact to stay aloft.

It is not about faster/slower plane. It is about thrust/weight. Slower plane with better thrust/weight ratio will climb better than faster one with less thrust/weight ratio.

Anything can move up if it has enough power, like a rocket, but a ww1 does not have enough HP/weight to climb without using wings for lift.

No they didnt, but it is very good example how wings just hinder you when you have enought thrust.
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#111 MiG-77

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Posted 09 June 2011 - 08:06

What this means it that no matter what the mass of the object you are dropping, it always "falls" at the same rate of acceleration (in a vacuum).

If you perform this same experiment in a medium of a given density (such as the atmosphere) the object will meet resistance (drag) due to the physical dimensions of the object moving through that medium.

Terminal velocity is the product of the above gravitational force (F) being balanced by the drag of the object. This holds true for WWI aircraft as well.

When you initiate a dive in, say the SE5a, as you increase speed your prop begins to generate less thrust and more drag. Your terminal velocity is still a product of gravity pulling you down and the resistance of drag (slowing down your rate of descent).

But this is exactly what I have been trying to say.
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#112 Sensenmann

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Posted 09 June 2011 - 08:12

ERkkk :?

I was sure somewhere in there you were saying that weight (mass) had nothing to do with the rate of acceleration of a falling object. It was in this statement:


"Weight" in free fall is just gravitanional force which is pulls objects in same speed. -> weight dont affect speed, density does (Density is not same as weight). So your claim that weight affect speed is wrong. Density and drag does. Also go and look weight difference of SE5a and Dolphin and then compare their size.

Perhaps I just misunderstood; Sorry. Carry on. I was never here.

:S!:
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#113 MiG-77

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Posted 09 June 2011 - 08:31

ERkkk :?

I was sure somewhere in there you were saying that weight (mass) had nothing to do with the rate of acceleration of a falling object. It was in this statement:


"Weight" in free fall is just gravitanional force which is pulls objects in same speed. -> weight dont affect speed, density does (Density is not same as weight). So your claim that weight affect speed is wrong. Density and drag does. Also go and look weight difference of SE5a and Dolphin and then compare their size.

Perhaps I just misunderstood; Sorry. Carry on. I was never here.

:S!:


Ah, yes but in first part I was referring to vacuum where all object have same "fall" speed. -> Gravitional pull is same and weight dont affect it. After that I was talking about density where air resistane is taken account.
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#114 Sensenmann

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Posted 09 June 2011 - 21:39

So, basically we agree, it is just a matter of semantics (on my end).

Anyway, I didn't see an answer to this:

Anyone have info for Lang 3800 and 3610 propellers diameter/pitch right now?
Ive had it in a WS specal (AC props) but its away from me for some time.

But I may have missed it.

According to the Dolphin Datafile, the LP3610A had a diameter of 2590 and a pitch of 2150. I assume that is in millimeters so that would be a 102" diameter and a 85" pitch.
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#115 Heliocon

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Posted 09 June 2011 - 23:37

ERkkk :?

I was sure somewhere in there you were saying that weight (mass) had nothing to do with the rate of acceleration of a falling object. It was in this statement:


"Weight" in free fall is just gravitanional force which is pulls objects in same speed. -> weight dont affect speed, density does (Density is not same as weight). So your claim that weight affect speed is wrong. Density and drag does. Also go and look weight difference of SE5a and Dolphin and then compare their size.

Perhaps I just misunderstood; Sorry. Carry on. I was never here.

:S!:
Holy crap, I give up, this is absurd. Density is determined by weight/volume. If you cant get over this simple concept there is not reason so continue a conversation as this is elementary physics as Sen pointed out. Use google, or take a basic physics class, and while this sounds arrogant - I know I am right because a year back I had to sit for 4 months and plug in equations in an astronomy course for escape velocity/lagrange points and irregular orbits.

Also my argument for se5a was that I thought at its theoretical maximum velocity the wings would be torn off sooner, while the dolphins wings would be more resiliant in a dive and therefore alow a sustained max speed dive.

Ah, yes but in first part I was referring to vacuum where all object have same "fall" speed. -> Gravitional pull is same and weight dont affect it. After that I was talking about density where air resistane is taken account.

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#116 Sensenmann

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Posted 10 June 2011 - 01:33

Holy crap, I give up, this is absurd. Density is determined by weight/volume. If you cant get over this simple concept there is not reason so continue a conversation as this is elementary physics as Sen pointed out. Use google, or take a basic physics class, and while this sounds arrogant - I know I am right because a year back I had to sit for 4 months and plug in equations in an astronomy course for escape velocity/lagrange points and irregular orbits.

Also my argument for se5a was that I thought at its theoretical maximum velocity the wings would be torn off sooner, while the dolphins wings would be more resiliant in a dive and therefore alow a sustained max speed dive.

Yes, density is determined by weight (mass) and volume. Density is fine for determining the terminal velocity of two objects of different masses if they have the same physical dimensions (i.e., an SE5a with a full fuel tank and another with a nearly empty fuel tank), though calculating the density of such an irregular shape would prove difficult. Ideally it is better to get a measure of the drag coefficient of each plane/object.

I think you and MiG are arguing the same point, but coming at it from different angles, and something is getting lost in translation.

As for your theory of the SE5a's wings coming off: The wings of the Dolphin have more surface area which will be put under greater stress due to resistance. Those wings are also attached to the fuselage through a few small contact points:

Image

These points were reinforced due to an accident where the wings separated from the body in flight.
Image


The SE5a, however, had a somewhat beefier design for the wing connection:

Image

There are several pictures in the link below that show the connection point for the lower wing…
http://thevintageaviator.co.nz/image/tid/114#


Then there is this juicy little tid-bit:

http://www.southsearepublic.org/article/1764/read/how_to_dive_an_se5a/australian_flying_corps/
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#117 Heliocon

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Posted 10 June 2011 - 02:01

Holy crap, I give up, this is absurd. Density is determined by weight/volume. If you cant get over this simple concept there is not reason so continue a conversation as this is elementary physics as Sen pointed out. Use google, or take a basic physics class, and while this sounds arrogant - I know I am right because a year back I had to sit for 4 months and plug in equations in an astronomy course for escape velocity/lagrange points and irregular orbits.

Also my argument for se5a was that I thought at its theoretical maximum velocity the wings would be torn off sooner, while the dolphins wings would be more resiliant in a dive and therefore alow a sustained max speed dive.

Yes, density is determined by weight (mass) and volume. Density is fine for determining the terminal velocity of two objects of different masses if they have the same physical dimensions (i.e., an SE5a with a full fuel tank and another with a nearly empty fuel tank), though calculating the density of such an irregular shape would prove difficult. Ideally it is better to get a measure of the drag coefficient of each plane/object.

I think you and MiG are arguing the same point, but coming at it from different angles, and something is getting lost in translation.

As for your theory of the SE5a's wings coming off: The wings of the Dolphin have more surface area which will be put under greater stress due to resistance. Those wings are also attached to the fuselage through a few small contact points:

Image

These points were reinforced due to an accident where the wings separated from the body in flight.
Image


The SE5a, however, had a somewhat beefier design for the wing connection:

Image

There are several pictures in the link below that show the connection point for the lower wing…
http://thevintageaviator.co.nz/image/tid/114#


Then there is this juicy little tid-bit:

http://www.southsearepublic.org/article/1764/read/how_to_dive_an_se5a/australian_flying_corps/

Yep you make a very good point there that I cant answer thats why originally I said its what I feel/think from seeing the planes and looking at their weights etc.

As for mis-communication, I know exactly what he is saying and if you go back and read I said density cannot be used easily here because the object is not uniform in density or shape, but Mig keeps repeating wrongly that weight is not a factor (it is because it determines density… - but density assumes an average uniform mass per volume) and that wings apparently dont contribute much to a planes climb rate - which is flat out wrong as his other ascertions on aerodynamics have been. You may very well be right about the se5a, I didnt come in here to argue over that, the argument here is over what simple physics are used in calculating a planes performance.
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#118 MiG-77

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Posted 10 June 2011 - 06:35

As for mis-communication, I know exactly what he is saying and if you go back and read I said density cannot be used easily here because the object is not uniform in density or shape, but Mig keeps repeating wrongly that weight is not a factor (it is because it determines density… - but density assumes an average uniform mass per volume) and that wings apparently dont contribute much to a planes climb rate - which is flat out wrong as his other ascertions on aerodynamics have been. You may very well be right about the se5a, I didnt come in here to argue over that, the argument here is over what simple physics are used in calculating a planes performance.

No, I am saying weight is not same as density. Density also take account size of object. As I made very clear in that earlier exampe. Heavier object will fall slower if it density is less than lighter object and that is what you really seem to missed. So weight itself dont determine anything in max fall speed (as it is proved also in vacuum, where air resistance is not factor, only gravitional pull). Weight is just value that is used to get density.

Also wing dont contribute much in climb rate as you can see any plane today or before (really, have you seen bombers with good climb rate. They do have huge wings :roll: ). It is the thrust/weigth ratio.

Anyway this dicsussion is going way offtopic and we can continue it in privately or you can open new thread of it. Only Dolphin post in here, for now one.
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#119 Sensenmann

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Posted 10 June 2011 - 06:54

So, before it is lost, I just wanted to make sure this piece of info does not go unnoticed.

According to the Dolphin Datafile, the LP3610A had a diameter of 2590 and a pitch of 2150. I assume that is in millimeters so that would be a 102" diameter and a 85" pitch.


Not sure if this data was already found… just making sure it is known.
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#120 MiG-77

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Posted 10 June 2011 - 07:13

Ill compine all relevant information in one post (and post this into beta boards aswell):

Attached File  dolphinperformance.PNG   463.26KB   445 downloads


Attached File  propellers.jpg   165.84KB   445 downloads



According to the Dolphin Datafile, the LP3610A had a diameter of 2590 and a pitch of 2150. I assume that is in millimeters so that would be a 102" diameter and a 85" pitch.

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