tail dragger conversion
10-20-2008, 12:34 PM
#1
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tail dragger conversion
Hi im converting my speed air into a tail dragger. I was hoping to use the main landing gear off my trainer but is this going to be strong enough? also any one with any help on this plese send it here.
10-20-2008, 01:19 PM
#2
Senior Member
My Feedback: (1)
RE: tail dragger conversion
ORIGINAL: speedair
Hi im converting my speed air into a tail dragger. I was hoping to use the main landing gear off my trainer but is this going to be strong enough? also any one with any help on this plese send it here.
Hi im converting my speed air into a tail dragger. I was hoping to use the main landing gear off my trainer but is this going to be strong enough? also any one with any help on this plese send it here.
Speed air,
1st make sure you get a good tail wheel that pivots and doesn't bind
2nd,
You need the aluminum part for the landing gear and it should be the size for your plane
Tape it in place with the wheels your going to use then balance the plane.
A lot of others told me I have mine mounted to far forward.
On my Avistar the front part of the strut gets wider at the top so I mounted mine with the axle just ahead of the leading edge and it lands like a dream
Vegas/
10-20-2008, 03:56 PM
#4
Senior Member
My Feedback: (1)
RE: tail dragger conversion
ORIGINAL: w8ye
I did this conversion last year this time and it flies like it is supposed to
I did this conversion last year this time and it flies like it is supposed to
Could be the angle of the picture.
The one on the ground is like mine.Ahead of the leading edge a bit
Nice trainers.
Vegas/
10-20-2008, 05:23 PM
#5
RE: tail dragger conversion
The gear on both planes is located behind F-2 which is the bulkhead former at the leading edge of the wing in the fuselage.
The plane on the ground is a H9 Ultra Stick 40 ARF which came from the factory as a tail dragger
The plane on the stand is a Sig LT 40 ARF which came from Sig with a nose wheel set up.
Both planes have a Dubro 40 size tail wheel bracket.
Neither plane has any nose over tendencies.
With a tail dragger, the more towards the CG you can have the main gear (Yet still in front of the CG), the easier it will be to land.
A forward location of the gear (In front of F-2 or more) will make the plane increasingly difficult to land. It will make the plane want to bounce back up in the air unless it is absolutely completely stall the moment it drops to the ground.
The above planes can be easily touched down on the mains first with the tail still flying and then let the tail settle to the ground as the plane losses speed.
The plane on the ground is a H9 Ultra Stick 40 ARF which came from the factory as a tail dragger
The plane on the stand is a Sig LT 40 ARF which came from Sig with a nose wheel set up.
Both planes have a Dubro 40 size tail wheel bracket.
Neither plane has any nose over tendencies.
With a tail dragger, the more towards the CG you can have the main gear (Yet still in front of the CG), the easier it will be to land.
A forward location of the gear (In front of F-2 or more) will make the plane increasingly difficult to land. It will make the plane want to bounce back up in the air unless it is absolutely completely stall the moment it drops to the ground.
The above planes can be easily touched down on the mains first with the tail still flying and then let the tail settle to the ground as the plane losses speed.
10-20-2008, 11:16 PM
#6
Senior Member
My Feedback: (1)
RE: tail dragger conversion
ORIGINAL: w8ye
The gear on both planes is located behind F-2 which is the bulkhead former at the leading edge of the wing in the fuselage.
The plane on the ground is a H9 Ultra Stick 40 ARF which came from the factory as a tail dragger
The plane on the stand is a Sig LT 40 ARF which came from Sig with a nose wheel set up.
Both planes have a Dubro 40 size tail wheel bracket.
Neither plane has any nose over tendencies.
With a tail dragger, the more towards the CG you can have the main gear (Yet still in front of the CG), the easier it will be to land.
A forward location of the gear (In front of F-2 or more) will make the plane increasingly difficult to land. It will make the plane want to bounce back up in the air unless it is absolutely completely stall the moment it drops to the ground.
The above planes can be easily touched down on the mains first with the tail still flying and then let the tail settle to the ground as the plane losses speed.
The gear on both planes is located behind F-2 which is the bulkhead former at the leading edge of the wing in the fuselage.
The plane on the ground is a H9 Ultra Stick 40 ARF which came from the factory as a tail dragger
The plane on the stand is a Sig LT 40 ARF which came from Sig with a nose wheel set up.
Both planes have a Dubro 40 size tail wheel bracket.
Neither plane has any nose over tendencies.
With a tail dragger, the more towards the CG you can have the main gear (Yet still in front of the CG), the easier it will be to land.
A forward location of the gear (In front of F-2 or more) will make the plane increasingly difficult to land. It will make the plane want to bounce back up in the air unless it is absolutely completely stall the moment it drops to the ground.
The above planes can be easily touched down on the mains first with the tail still flying and then let the tail settle to the ground as the plane losses speed.
I picked up the gear at a local shop and it's about 1 size to small
My apartment isn't big so it's hard to get a good indoor pic but I can land aand fly mine like you do and keep the tail wheel up off the ground
Vegas/
10-21-2008, 02:29 AM
#7
Senior Member
RE: tail dragger conversion
It's pretty much accepted throughout the airplane industry that the landing gear be placed relative to the CG.
They look at where the tires touch the ground. Some people call that the footprint. And where the CG is. Sometimes they actually work out where it actually is in the airplane, not just where it's projected to be on the wing. (Because it's usually not really where the wing is, and for designing the gear, that matters.) And they design the gear to put the footprints a certain angle ahead of the CG. The attached picture shows what one model designer suggests is a good angle.
In practice, the angle is really a range of angles, but don't usually see a picture or drawing that shows more than one. And designers know that in practice (especially with full scale airplanes) the CG usually moves throughout the flight, so that also needs to be considered. They also know that there are more considerations than just landing where the location of the footprint to the CG does things that need to be thought about. For example, ground handling is affected. I've got a Corsair that is tippy with a full tank of fuel, and isn't when it's almost dry. Why? The fuel tank is actually fairly oversized for the usual engine and it's entirely ahead of the CG. When it's full, all that excess weight wants to lift the tailwheel off the ground. And it wants to tip the nose into the ground. Yup, there are some other good reasons to place the footprint where the industry, and experienced model designers, have figured out works.
BTW, I plan to retrofit that big tank with one about 2/3 it's size. And I plan to place the smaller one with it's rear where the rear of the original is. That big one has proven the engine draws perfectly from that distance. Heck, the smaller one might get placed a bit further back just to find out if the engine would draw with the tank closer to the CG. It's good to have some weight on the tail wheel, but even "gooder" to have your fuel at the CG. Then you get no trim change at all.
They look at where the tires touch the ground. Some people call that the footprint. And where the CG is. Sometimes they actually work out where it actually is in the airplane, not just where it's projected to be on the wing. (Because it's usually not really where the wing is, and for designing the gear, that matters.) And they design the gear to put the footprints a certain angle ahead of the CG. The attached picture shows what one model designer suggests is a good angle.
In practice, the angle is really a range of angles, but don't usually see a picture or drawing that shows more than one. And designers know that in practice (especially with full scale airplanes) the CG usually moves throughout the flight, so that also needs to be considered. They also know that there are more considerations than just landing where the location of the footprint to the CG does things that need to be thought about. For example, ground handling is affected. I've got a Corsair that is tippy with a full tank of fuel, and isn't when it's almost dry. Why? The fuel tank is actually fairly oversized for the usual engine and it's entirely ahead of the CG. When it's full, all that excess weight wants to lift the tailwheel off the ground. And it wants to tip the nose into the ground. Yup, there are some other good reasons to place the footprint where the industry, and experienced model designers, have figured out works.
BTW, I plan to retrofit that big tank with one about 2/3 it's size. And I plan to place the smaller one with it's rear where the rear of the original is. That big one has proven the engine draws perfectly from that distance. Heck, the smaller one might get placed a bit further back just to find out if the engine would draw with the tank closer to the CG. It's good to have some weight on the tail wheel, but even "gooder" to have your fuel at the CG. Then you get no trim change at all.
10-21-2008, 07:33 AM
#9
Senior Member
My Feedback: (1)
RE: tail dragger conversion
My CG is fine and the plane is in proper balance.
Where I screwed up was I used the landing gear for a lighter plane and the nose should be higher.
I never measured it but I think if I had 12* instead of the 20* shown I consider myself to be lucky.
I wanted to change the landing gear or go with bigger/thinner spoked wheels but it flies nice and I don't have a problem.
I will take that measurement later and let you know what it is.
Thanks for the information
Vegas/
Where I screwed up was I used the landing gear for a lighter plane and the nose should be higher.
I never measured it but I think if I had 12* instead of the 20* shown I consider myself to be lucky.
I wanted to change the landing gear or go with bigger/thinner spoked wheels but it flies nice and I don't have a problem.
I will take that measurement later and let you know what it is.
Thanks for the information
Vegas/
10-21-2008, 07:43 AM
#10
Senior Member
My Feedback: (1)
RE: tail dragger conversion
ORIGINAL: w8ye
That's a good looking Avistar. That's the way they should come from the factory.
I used the gear for a H9 Super Stick 60 on my LT40. I.L.A.R.
Jim
That's a good looking Avistar. That's the way they should come from the factory.
I used the gear for a H9 Super Stick 60 on my LT40. I.L.A.R.
Jim
I sort of like that plane better then the bigger trainers.
Just the right size and a change to a .46 engine size is all need to keep me happy.
When I get out again i'll take some pictures of it on the ground.
It looks 100% better.
Yesterday again was gusty and I had to go into the weeds for another landing again
But this time the tail picked up a tiny tear on the left horizontal stab but some clear packing tape took care of it.
Still thinking if I should put the bigger landing gear on or not because I have no problems with it.
Vegas/
10-21-2008, 07:54 AM
#11
Senior Member
My Feedback: (1)
RE: tail dragger conversion
ORIGINAL: w8ye
That's a good looking Avistar. That's the way they should come from the factory.
I used the gear for a H9 Super Stick 60 on my LT40. I.L.A.R.
Jim
That's a good looking Avistar. That's the way they should come from the factory.
I used the gear for a H9 Super Stick 60 on my LT40. I.L.A.R.
Jim
When you have time can you give me a measurement from where the bend is on the landing gear on the bottom of the plane to the wheel screw hole?
Maybe my gear struts are OK.
Bob
AF2Q
10-21-2008, 08:12 AM
#12
Senior Member
RE: tail dragger conversion
ORIGINAL: Whirley Bird
My CG is fine and the plane is in proper balance.
Where I screwed up was I used the landing gear for a lighter plane and the nose should be higher.
I never measured it but I think if I had 12* instead of the 20* shown I consider myself to be lucky.
I wanted to change the landing gear or go with bigger/thinner spoked wheels but it flies nice and I don't have a problem.
I will take that measurement later and let you know what it is.
Thanks for the information
Vegas/
My CG is fine and the plane is in proper balance.
Where I screwed up was I used the landing gear for a lighter plane and the nose should be higher.
I never measured it but I think if I had 12* instead of the 20* shown I consider myself to be lucky.
I wanted to change the landing gear or go with bigger/thinner spoked wheels but it flies nice and I don't have a problem.
I will take that measurement later and let you know what it is.
Thanks for the information
Vegas/
The CG is always worked out according to how the airplane is to fly. The importance of the CG is in balancing the airplane in the air. If it's not in the proper balance in the air, it comes back down. No matter where the gear is attached.
But to place the tires where they give the least chance of problems, they are positioned relative to where the CG is not the other way around.
Shorter landing gear will place the footprint at a different angle than longer gear places it. In fact, with your short gear it needs to be attached further aft simply to keep the footprint from being too far forward. The length of the gear also has something to do with where the gear should be placed. In the case of your model, if you plan to swap out that short gear for longer, expect to get different ground handling. The posters who've suggested that the gear is too far back are probably advising you based on their experience. And they probably used "normal" length gear.
