Global announcements



Post new topic Reply to topic  [ 324 posts ]  Go to page Previous  1, 2, 3, 4, 5, 6, 7 ... 33  Next
Author Message
Offline WW1EAF_Ming
Глас / Talking Guru
Posts: 2552
During the test I did find the D.III a little more difficult to handle than the D.II. The D.III liked to side slip towards the ground. It took me some time to get in the groove of making a good, tight turn.

Good stuff BB.

Yes there's also the vertical component to consider, with some planes having tight turns to begin with but then descending in that forced-slipping, while other planes will be able to maintain the flat turn. Flattish anyway. Flatter. I know what I mean :) (like in Il-2 while we flat-turn in a Hurricane while the E4 perches above)

In that nice WW1-Russia movie that's around there's a plane (later on) with a 400HP engine. That'll be a turner I bet. Or anything it wants :)

But the power of the engine must be very important is what I mean for maintaining the flat-turn without descending, slipping down when attempting to maintain the same height, letting a plane with a less powerful engine drop down in the turnings

Ming
Intel Core i7 920 D0 Stepping 2.66Ghz
Gigabyte EX58-UD5
Gigabyte GTX580 262.99 WHQL drivers
OCZ Gold 6GB DDR3 PC3-12800C8 1600MHz
Asus D2X Xonar soundcard
Windows 7 x64
Corsair HX 1000W
MSFFB2 native Win7 drivers
TIR5 latest 5 drivers
Joined
Fri 08 May 2009, 12:31

#31 Post Tue 29 Jun 2010, 09:16

Online Chill31
Глас / Talking Guru
Posts: 1696
hq_Reflected wrote:
Topic: SE5a Stall speed:

RoF data (confirmed by tests: 56 mph (90 kph) - 100% fuel, no ammo

real deal: 50 mph landing speed, 45 mph (max) touchdown speed.

Attachment:
SE5a flight characteristics F904 flight report 1977 @ Shuttleworth.rar


(Thanks, Catfish ;) )

also:

Quote:
The tail is raised and
within a few seconds a flying speed of around 50 to 55 mph is reached. The aircraft flies off
the ground with a will and settles into a natural climb at about 60 to 65 mph.
Both control power and harmonisation are good. The SE is very similar to the Tiger moth but
with higher roll rate and slightly heavier controls. There is also the absence of the inertia
caused by the Tiger‟s heavy centre section fuel tank. The climb is rapid and as briefed, slight
oil mist/smoke is seen to emit from the radiator area and the starboard side of the engine
cowl. After take off, the rpm are reduced to 1900 to reduce engine wear, and coolant
temperature and radiator flaps are monitored and regulated respectively.
An appropriate height for stalling is soon reached and the slow end of the flight envelope can
be essayed. First, engine management must be carried out and the radiator shutters are closed
as the throttle is retarded. The latter must be done slowly as fast engine modulation brings
unwanted stress on the engine and may lead to a damaging backfire. The stall break occurs at
about 45 mph
with more than adequate buffet as a warning and a wings level nose drop as an
indicator.


Roger ‘Dodge’ Bailey The Shuttleworth Collection Old Warden Aerodrome Biggleswade, Beds, UK (Original SE5a)

Quote:
Next, slow flight and stalls are explored, a good
idea to check before landing.... again nothing unusual other than the fact that this airplane is rather
easy to fly. Adjusting the elevator trim allows the SE5a to be flown hands off something I’m not used
to in a WW1 fighter. A few more stalls are investigated and a power off stall speed of 43 mph is
noted.


(Vintage aviator - replica)


Frank Tallman "flying the old planes"
Flying an original SE5 with a Hisso engine


"Settling back to cruise, I locked my belt and brought the stick back for a stall. It pays off gently, but with a sharp right-wing drop at an indicated 52 mph. Invariably, in a stall, the right wing dropped."

*Personally, I find it very odd for him to have a power off stall at 43 mph. given that he took off at 50-55...Your stall speed in ground effect is LOWER than your stall speed flying up in the open air AND it should be significantly lower than your POWER OFF stall speed...I can explain the physics/aerodynamics if you really want...
Joined
Mon 06 Jul 2009, 17:37

#32 Post Tue 29 Jun 2010, 22:47

Online hq_Reflected
Глас / Talking Guru
User avatar
Posts: 4402
Chilli, I don't know what explanation do you have for this, but I'm all ears. The Shuttleworth SE is a real one, real engine, real guns (no ammo) real fuel tanks, same weight. It touches down at 45 mph, and we, in RoF stall at 56. That's 125% ! A huge difference...

Oh, and by the way, the SW SE has a 200 HP Viper, while the SE flown by Tallman had a 180 HP Hisso.
http://www.facebook.com/wearereflected
Joined
Thu 08 Oct 2009, 15:40

#33 Post Wed 30 Jun 2010, 06:10

Online Kwiatek
Неумолкаемый / Chatterbox
Posts: 672
" 3) Pfalz D.IIIa - maneuvers too good, horizontal speed too low "

Good to hear about planned fix for Pfalz DIIIa unrealistic manouvers in ROF but i wonder what with some other German planes like Albatros and Fokker DVII?

I post about these in other topic but i think Neoqb should check these things also.


I made 3 short videos with Se5A, Albatros DVa and DVII when i test how they react in sharp turn and pull up with maximum deflection of stick.


First video is how plane with good FM should stall in hard turn. Se5a stall immidietly in such turn when reach critical angle of attack.

http://www.youtube.com/watch?v=88PoK6Q05ck



Second and Third video is with German planes Albatros Dva and Fokker DVII. They dont have accelerate stall at all and could do some unrealistic manouvers. Look how they make loop - Fokker DVII could make a loop at maxium deflection of stick at high speed near in a spot ( burn all energy in such manouvers but has not accelerated stall and make manouvers near in a spot)


Albatros:

http://www.youtube.com/watch?v=tMW4-oRF9uE

DVII

http://www.youtube.com/watch?v=Xg1ZW7jl4-U



Here are pilots notes about these planes :


Se5A

"To get a better feel for what this airplane can do, steep turns, lazy eights and wingovers are attempted, all easily carried out but an excessive amount of adverse yaw is experienced.
The adverse yaw is easily compensated for, by balancing aileron application with rudder and doesn’t prove to be a problem at all. Next, slow flight and stalls are explored, a good idea to check before landing.... again nothing unusual other than the fact that this airplane is rather easy to fly. Adjusting the elevator trim allows the SE5a to be flown hands off something I’m not used to in a WW1 fighter. A few more stalls are investigated and a power off stall speed of 43 mph is noted.

With the power pushed up a bit, a conservative top speed of 115- 120 mph is achieved!
I would expect during wartime even this top speed would be increased to the reported numbers of about 138 MPH. The only aircraft that could come close was the Fokker DVII, so the SE5a was faster than anything out there and very competitive with the later produced DVII. The performance doesn’t seem to diminish with altitude either, it can maintain 120 mph right up to about 15,000 ft. After the formalities of recording figures for temperatures, pressures and airspeeds, it’s time to really get a feel for the new plane. I am still amazed that it is so easy to fly and feels so stable. Turns in either direction are simple as long as they are coordinated with the rudder."


"At the time the SE5a entered service, pilots were arriving at the Front with fewer than 20 hours of flying time, so a plane that could be flown by pilots of limited flying experience was very well accepted. There were far fewer accidents than those experienced with many of the Sopwith or Nieuport designs. While the highly maneuverable designs were better suited to skilled pilots with many hours of flight time, the SE.5a design was entirely different. Easy to fly, stable and forgiving, even a mediocre pilot could capitalize on the steadiness of the aircraft, firing at the enemy from further away with a greater degree of accuracy."


Besides:

Se5A had lower take off weight and bigger wing area then German Scouts or DVII so it had lower wingloading. It had less camber airfoil then Albatros or Pfalz DIIIa so i expect it has little lower CLmax but other hand it had more gentle stall above critical angle of attack then German Scouts. These really prety good is confirmed by German pilots opinion about German Scouts:

Albatros DIII:

" Apart from its structural deficiencies, the D.III was considered pleasant and easy to fly, if somewhat heavy on the controls. The sesquiplane arrangement offered improved climb, maneuverability, and downward visibility compared to the preceding D.II. Like most contemporary aircraft, the D.III was prone to spinning, but recovery was straightforward."


Pfalz DIII:

"German pilots variously criticized the Pfalz’s heavy controls, low speed, lack of power, or low rate of climb compared to the Albatros. The D.III slipped in turns, leading to crashes when unwary pilots turned at very low altitudes. Moreover, the Pfalz stalled sharply and spun readily. Recovery from the resulting flat spin was difficult, though some pilots took advantage of this trait to descend quickly or evade enemy aircraft"



Se5A:

" To get a better feel for what this airplane can do, steep turns, lazy eights and wingovers are attempted, all easily carried out but an excessive amount of adverse yaw is experienced.
The adverse yaw is easily compensated for, by balancing aileron application with rudder and doesn’t prove to be a problem at all. Next, slow flight and stalls are explored, a good idea to check before landing.... again nothing unusual other than the fact that this airplane is rather easy to fly.

"Easy to fly, stable and forgiving, even a mediocre pilot could capitalize on the steadiness of the aircraft"


And i think Neoqb did pretty good job with FM of SE5a ( besides these stupid elevator issue and absence of elevator trimm) - these planes fly very natural, have accelerated stall but is quite easy to fly and stall warning is very good.

I cant say the same about German Scouts and Fokkers by Neoqb. They dont behave like combat planes but rather like RC models.

I hope Neoqb will check these things carefully and make all German planes to fly more like RL combat planes not flying kites.

I think the same like Pflaz DIIIa it should be checked and fixed in the same way.
Joined
Mon 13 Jul 2009, 09:56

#34 Post Wed 30 Jun 2010, 20:32

Online Chill31
Глас / Talking Guru
Posts: 1696
Kwiatek, you need to have sources for your pilot notes...the name of the author and book is a good start. Otherwise, we can simply put in quotes whatever we want...
Joined
Mon 06 Jul 2009, 17:37

#35 Post Thu 01 Jul 2010, 14:09

Online Chill31
Глас / Talking Guru
Posts: 1696
Reflected,

My goal in posting conflicting data to yours is NOT to prevent changes from being made. Each plane of the same type will have a different "personality" and will fly slightly different from the one sitting right next to it on the flight line. So I like to take all the data (which is probably very good) and average it so that you are right in the middle.

Anyway, to explain why a 43 mph power off stall paired with a 50-55 mph take off speed contradicts itself a little bit. Also, when accompanied by Frank Tallman's info, I think 43 mph power off may be a little off.

When you perform a power off stall at altitude, the only vertical force acting on the plane to keep it in the air is lift produced by the wing. The plane begins to fall (stall) when the weight component toward the earth is greater than the lift produced by the wing. With power off, this could be 60 mph lets say. Now if I do a power on stall, there are 2 vertical forces keeping the plane in the air: lift from the wing, and thrust from the engine. This means that the engine/propellor can carry some of the weight that the wing would have to carry and the plane will now stall at a lower airspeed than 60.

On to ground effect...ground effect is where the earth reduces induced drag and essentially makes the wing more efficient. This is why you can actually take off in most airplanes well below safe flying airspeed and upon exiting ground effect (about half your wingspan) you can suddenly be falling back to earth. So a landing speed of 43 mph using a 3 point landing (tail low stall) means that his out of ground effect stall should be higher than 43mph.

Also keep in mind, that higher AoA (angle of attack), such as near stall, introduces more error into the airspeed indication. If there are any variations between aircraft pitot systems, this could account for some variation in numbers (another reason to average data)

Hope this helps...
Joined
Mon 06 Jul 2009, 17:37

#36 Post Thu 01 Jul 2010, 14:26

Online hq_Reflected
Глас / Talking Guru
User avatar
Posts: 4402
OK Chili, thanks for expaining, I understand what you wrote - and learned a lot from it. However, I asked a real pilot and he said that the touchdown speed is always superior to the stall speed. Also, no one tries to take off until a safe speed is achived, hence the 50-55 mph takeoff speed (which is still lower than our 56 mph stall speed) The touchdown speed is "maximum 45 mph" according to the document. Of course, planes should have a personality, but 43 mph vs 56 is a huge difference, that's what made me think in the first place. I tried to look into many things:
-Is the SW SE5a lighter than a wartime one? - no, apart fro mthe ammo load
-Is it an original one, with the original parts (same engine, etc..) - yes

So even if data derived from tests made with it can not be carved in stone, still they should be a very good reference, and again, it's 43 vs 56.

Also, Tallman's SE is not a 100% original one, it has a different (weaker) engine, so we should consider those data less likely to be accurate than the SW report (which is a wartime SE minus ammo)

So even after considering your points I think the SE5a's stall speed should definitely be well below 50mph at worst. :roll:
http://www.facebook.com/wearereflected
Joined
Thu 08 Oct 2009, 15:40

#37 Post Thu 01 Jul 2010, 18:01

Offline NakedSquirrel
Beta-tester
User avatar
Posts: 1133
Mogster wrote:
Image


squid wrote:
Okay, put it another way.

An DH2 can out turn a DR1?


I think think we are missing a key point here. Something about this chart was bugging me and it finally dawned on me why. So let me put this a different way to punctuate why: A Sopwith Dolphin could easily out turn a Bf109, why did the British ever bother with the Spitfire?

OK, so it's a bit of an exaggeration since the Bf109 can go about 400 kph faster, but I think it makes the point that turning radius won't mean the same as turn speed. I think a DH2 could make a tighter circle than an Dr1, but a Dr1 would probably make its full circle in half the time. I don't think the DH2 would stand much of a chance in a dogfight against the Albatros fighters because of its low speed and terrible climb rate.
Callsign "Naked Squirrel"
Joined
Thu 06 Aug 2009, 19:15

#38 Post Fri 02 Jul 2010, 20:36

Offline sturmkraehe
Неумолкаемый / Chatterbox
User avatar
Posts: 967
Turn radius Chart is based on wing loading calculation as clearly stated by the note. Therefore not a reliable definite source ... so carefull with this one. It is NOT an original source.
Image
Joined
Sun 02 Aug 2009, 12:12

#39 Post Fri 02 Jul 2010, 20:50

Online ImPeRaToR
Beta-tester
User avatar
Posts: 7900
wing loading is also relative and the effective lift of the wing area depends on the gap and wing chord (afaik).
Non quia difficilia sunt, non audemus, sed quia non audemus, difficilia sunt!
Joined
Sun 18 Oct 2009, 22:18

#40 Post Fri 02 Jul 2010, 21:57

Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 324 posts ]  Go to page Previous  1, 2, 3, 4, 5, 6, 7 ... 33  Next

Who is online

Users browsing this forum: No registered users and 2 guests

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to: