Landing gear speed database
 

With electric gear becoming more mainstream, maybe it would be good to have a database here of various full scale jets showing their retraction sequence and gear door opening/closing speed. I've seen quite a few posts asking about scale speed.

Here are a few to begin with. Feel free to add as many JET related full scale videos you may have seen.

F-16
[youtube]http://www.youtube.com/watch?v=uBfPdDzyekE[/youtube]

[youtube]http://www.youtube.com/watch?v=BVMvhDVReUU[/youtube]



F-18
[youtube]http://www.youtube.com/watch?v=nkgRM9CWWp4[/youtube]

[youtube]http://www.youtube.com/watch?v=XnFBUCOSN4s[/youtube]



A-10
[youtube]http://www.youtube.com/watch?v=iz9UIcP-4_w[/youtube]



L-39
[youtube]http://www.youtube.com/watch?v=kR4ld9HE8fE[/youtube]

RE: Landing gear speed database
 

F-5

[youtube]http://www.youtube.com/watch?v=1tkS6Ruh2Y4[/youtube]

RE: Landing gear speed database
 

Heinkel HE-162

[youtube]http://www.youtube.com/watch?v=UlRL320cCGY[/youtube]


Cool restoration project. Worlds first single engine jet fighter. Check out the photos http://memorial.flight.free.fr/He162uk.html

RE: Landing gear speed database
 

B-737

[youtube]http://www.youtube.com/watch?v=9uPBgOlhuLc[/youtube]



MIG-23

[youtube]http://www.youtube.com/watch?v=yxK6F9AbLLc&feature=results_video&playnext =1&list=PLCE09538D6175C3BD[/youtube]



C-5 Galaxy

[youtube]http://www.youtube.com/watch?v=hg7d8zMca6g[/youtube]

RE: Landing gear speed database
 

L-1011 TriStar

[youtube]http://www.youtube.com/watch?v=RJSyiLWtCUk[/youtube]

RE: Landing gear speed database
 

Lear 35A

[youtube]http://www.youtube.com/watch?v=r6Cz39nwqjk[/youtube]

RE: Landing gear speed database
 

F-104 Starfighter

[youtube]http://www.youtube.com/watch?v=mhdAX8WHzBk[/youtube]

RE: Landing gear speed database
 

A-4 Skyhawk


[youtube]http://www.youtube.com/watch?v=eq97pGsiakM[/youtube]

RE: Landing gear speed database
 

F-35

[youtube]http://www.youtube.com/watch?v=cfD63we7Ptw[/youtube]

RE: Landing gear speed database
 

Holy crap you've done some homework! Good job!

RE: Landing gear speed database
 

Great info John, thanks !!

RE: Landing gear speed database
 

Great, thanks! That MiG undercarriage is the real trans former!

TP.

RE: Landing gear speed database
 

Good post John.
I have electric gear in some of my models and am converting more.
Ill admit, the full size gear retract alot faster than I thought. They seem much slower on the videos Ive seen of jets taking off, but you cant dispute the videos you have posted.
Obviously air systems are much faster and far from scale, especially if no restrictors are installed. The speed of air isnt as consistent either. Maybe some of the new electrics are too slow. I think alot of guys will be getting away from air and going with electric. you cant beat the reliability of electric.
The problem with electric gear are that if you have a really large set of gear to retract, you will be forced to use actuators that are geared down for strength and will be slower. Faster actuators not as strong. My first set on my Tomahawk Hawk were about 5 seconds but just werent strong enough. They didnt always retract. I had to gear down and now Im probably closer to 8 seconds. They are much stronger now and work perfect.
Using actuators on doors will probably never be close to looking scale. I dont think they can ever be as fast as the videos you posted. Servos for doors can mimic full size the best.
Using different voltages can slow or speed up electric gear. Im using a 9.9V on my Down and Locked and I like the speed they produce. The 7.4 was probably over 10 seconds.
Ive got two sets of gear converted and another one working now and am pulling out another 3 sets to send asap.
Thanks for the videos.
Scott

RE: Landing gear speed database
 

Looking at the FEJ F16 video of electric gear, its not the gear that are that slow, but rather the doors.
Scott

RE: Landing gear speed database
 

F-15

[youtube]http://www.youtube.com/watch?v=OzFB4x3bY[/youtube]

For some reason this embedded video is not showing. If you copy the link below and paste it in your browser the video will show. Strange...

http://www.youtube.com/watch?v=OzFB4x3bY

RE: Landing gear speed database
 

Scott, I think you are right about gear doors. Servos are probably better suited. I still have not made the switch to anything electric. But, I think my Tucano gear will be sent in for conversion soon

RE: Landing gear speed database
 

Awesome. Thx for the videos

RE: Landing gear speed database
 

HOLD ON A MINUTE FOLKS....

sorry to provide bad news, but before we get all excited about the ger in the vids, remember this: Hyd pressures provided by maintenance/test equipment may well be a lot LESS than provided by the aircraft's own engine or electrically driven pumps !

I'd say it's safe to say that the true speed of the gear in normal conditions is not any slower then that shown in the vids, but all other bets are off....

RE: Landing gear speed database
 

Hold on another minute.

Just how fast do we think model gear SHOULD retract?

I have seen a video of a model airliner (DC9) with electric retracts and gear doors. (about 1/10 or 1/12 scale I think)
The pilot hit the retract switch just after takeoff, and the retract speed looked about right, but by the time the sequence had finished and the doors were closing, the model was half way round the circuit and up to full flying speed. By the time the gear doors had opened, and before the legs started to retract,the model was at a considerable "scale" height by which time on the full size it would all be over.

When we fly a scale model we are distorting (compressing)time, so we need to consider how much we speed up gear retraction compared to full size. Twice as fast, five times as fast or what?

I think what we should be considering viewing a video of the full size taking off, and noting what height it looks once the gear is up. If the full size is "clean" by say500 feet, should a 1/5 scale model be clean by 100 feet?

RE: Landing gear speed database
 

That debate is also closely tied to the scale speed debate, and here the general consensus (and scale judges as well) is that if it looks right, it is scale looking. Size has nothing to do with the models gear retraction speed, It is all about what looks right and as close to the original plane as possible.

Same goes for when you demonstrate a mechanical option for the judges. Let's say a flaps demonstration. They want to see scale like speed and not a speed multiplied by whatever your models scale is.

So, for "correct" looking speed of mechanical options on a model, we would mimic the full size plane as close as possible.

RE: Landing gear speed database
 

Yes, that is kind of what I am thinking about. It should look right,

So what would look right?

I think it should take about the same segment of the climb out as it takes on the full size. It should relate to the flight path.

My impression of the DC9 model was that the retract sequence took too much of the circuit, too much distance and time.

RE: Landing gear speed database
 

I should not relate to an airliners flight path. It would not make sense so simulate an airliners scale flight.
A scale flight of a typical 1/10 scale airliner would be something like this:

Climb out to 3300 feet (FL330 simulated) then a fairly straight flight for 100 miles at 60 mph followed by a landing in a different city :)

On a scale model you want to simulate mechanical movement of gear/flaps/sliding canopy etc. at actual speed. no question about that in terms of scale competition.

RE: Landing gear speed database
 

Airliners do not just make straight flights, holding patterns are typical of the type of manoeuvre that a model jet might make, if done slightly lower than scale altitude. I go with Alasdair's point that the wheels should be retracted at a speed that looks right and will certainly not be as slow as full size. In fact with a model airliner the critical thing is the way that the landing gear flaps etc are deployed and the landing and takeoff is achieved.

I think with most of our models the main thing that shows them up as being models is the ridiculous speed that some people fly at. If you watch a master like Ali he will fly an very modest speed with scale jets and indeed looks all the better for it rather than the flat out low pass.

John

RE: Landing gear speed database
 

John, this database of gear retraction speed is not about where and when gear should be retracted. It's simply showing how the full scale planes look when doing it.

And I do know a little bit about scale flying myself... I actually beat Ali in the Pro class at Top Gun this year :) when I take off, my wheels retract right after take off and before a turn is started. It looks right, feels right and that's all the judges care about.

RE: Landing gear speed database
 

Highhorse, your point makes sense, but looking at inflight gear operation does not seem to offset the timing much

This video has 7 F-18's taking off right after each other. Note that the typical gear retraction speed is somewhere between 3 and 4 seconds. Just like it is on the ground video.

Interesting aspect is that two of the planes have a noticeable delay on the left main. By a couple of seconds actually.

[youtube]http://www.youtube.com/watch?v=OFtiB7pHfjI&feature=youtube_gdata_player[/youtube]