dabigboy

Howdy all,

First post here. Been into R/C since getting a Cox Sundancer 9 years ago. About 7 years ago I got an already built, barely flown Tiger II. It's been an awesome plane, and still serves as my every-day flyer, but it's starting to show its age. I'm planning on recovering it and perhaps changing a few things.
It's got a tricycle gear setup, I'd like to convert it to a tail dragger. I browsed the forums here a bit and it seems most people who decide on the tail dragger setup move the gear mount blocks forward during assembly. The gear wires on my kit (which I assume are stock) have a slight angle between the bend that goes into the wing and the actual leg/strut, they are mounted so the gear angle back a bit. I tried swapping them, and the plane actually sits tail-down, but it's a fine balance and would not work in practice. Just wondering if anyone has attempted a similar conversion on a Tiger made for tricycle gear? I'm thinking I could just bend the gear wires a bit more, but I am somewhat worried that this would lead to excessive gear flex on landing, plus decreased ground clearance (it's pretty close as-is, and tail-down the plane is still at almost a level attitude).
One other thing I was wondering about.............is there any chance at all that a fixed-gear .40 size Tiger would accept a retract conversion? Would make it look a little sharper in-flight, and maybe bump the speed up a bit.
Thanks!

-Matt Bailey

Tall Paul

I've done that mod on a Tiger II and Tiger 60.
In essence, the main gear mounting block on the II is mounted behind the spar, with suitable reinforcement.
On the 60, I made retracts fit just ahead of the spar.
The "gear in front of the wing" mod is easy, and works OK, but looks dorky to me.
My Tigers can get up on the mains during takeoff and stay there for as long as I feel like, with no darting to either side.

bojangle

Hi Matt, welcome to the Forum

I have a Super Sportster which is somewhat similar to the Tiger in setup. I installed 2 sets of blocks in the wing, so I can convert from trike to dragger.

Just bending the struts won't get the wheels far enough forward. Since you plan to re-cover anyway, I would suggest you make new blocks, set them about an inch back from the leading edge. The struts will angle forward, with the center line of the axle about plumb with the leading edge. Then you could use your existing gear.

Some make the conversion by adding a plywood plate under the chin block and installing a Dural aluminum gear. I personally like the wide stance of the wing mounted gear. Be careful not to get the gear too far forward, which will induce more ground looping. A little "toe-in" helps ground handling.

Obviously, you will need a steerable tail wheel assembly of your preference.

I'm sure others will be adding to this post, some who have made the actual Tiger conversion, so keep checking in. As for retracts, I imagine they would work. I've never used them, so others should comment on that.

BOB

Tall Paul

I remembered I still have the T-II plans.. here's the fixed gear mod.
Retract is similar, with more support for the retract mechanism.

bojangle

Paul
I notice some planes have the axle just behind the leading edge, (my sportster), others, (like the T-II pic) are a little further back. My Cub has the axle directly under the LE. Is the "sweet spot" different for various planes, or is there an optimum average position? (or trial and error)

I only have 2 draggers, they track great. Most of my planes are trikes, so I never got into the study/science of conventional gear.

BOB

Tall Paul

I've noticed that for tail-draggers, with the wheels relatively aft, they track straighter. My criteria is being able to see the front of the tire when looking straight down at the wing... more or less.
The 4* family seems to have the wheels too far forward. Many of them go multi-directional on landings...,
The approved mod to the Tiger 60 ARF puts the wheels too far forward, in my estimation, but the planes appear to handle OK.

dabigboy

Cool, thanks for the plans snippet Paul. Hmmm gear is still close to CG, with that feature plus the wide stance gear this should be one sweet handling tail dragger.

I do know having the gear forward should make the ground handling less stable and the plane should tend to swap ends more, due to increased moment of CG in relation to gear. That's one reason I wish just swapping the gear would work, but alas it would tip over way too easy.

I think for simplicity I'm just gonna stick with the fixed gear model, that way I can just make the new block and mount my existing gear (I've never tackled retracts before). I see the plans recommend lite ply ribs in this area for the conversion. Do you think I'll need to make a couple of ply ribs and laminate them to the existing balsa ribs to beef up the area where the new blocks will mount? Of course, if I'm lucky, the guy who built this thing used the ply ribs, just for grins (it wouldn't surprise me, everything about this model is first rate).

Got another question about this "update". I read somewhere (kit review I think) that using dual aileron servos might help avoid the aileron flutter that's been a problem on the Tiger. At high speed my model sometimes makes a fluttering noise, but I'd assumed it was the relatively flimsy tail feathers (or even the horizontal/vertical stab covering, it's a bit loose on this model). Any of you guys try dual servos, and did it fix the problem? Did you mount the servos inverted, with the drive shaft exposed, or at 90* with just the control horn sticking out? I'm thinking of epoxying hardwood blocks in a rectangle on two ribs and the back of the spar, and bolting a hardwood plate onto that with the servo mounted in the plate. That way I can mount the servo at 90* for looks and streamlining, but still get to it later if need be.

One more question, perhaps I should just make this one a seperate post as it's rather generic.....I'd like to tint the canopy, it would look a lot better with the color scheme I'm planning. What's the best way to do this? I thought about holding the canopy near a spray can and letting the overspray coat it, but I suspect that would make it look spotty. What about literally "smoking" it, like putting it near a candle or something and letting it tint the surface? I've seen this happen on cars that have had fires.

I almost hate to recover this bird, whoever built it did an awesome job on everything. Good construction and a neat, professional-looking covering job. But it's so very old.....and I want something a little more exciting than generic white Tiger trim on pink......yes, this plane is pink! :P I have a modern, pseudo-scale scheme in mind, red-over-white with gradually smaller stripes on the wingtips (various new general aviation planes sport this scheme).

Anyway........sun is out, birds are singing, batteries are charged, time to take this thing out for the first flight of the new season.

-Matt Bailey

Tall Paul

For the new ribs, I'd just copy the fronts of the ribs already there in lite-ply, notch those out for the mounting block, and paste the lite-ply new ribs next to them.
Dual aileron servos ARE needed. The ailerons on the Tigers are so high aspect ratio there's no torsional stiffness with the center-mounted servo. I expected the II to flutter, and it did on the first flight. Out with the single servo, in with two.
I've done both mountings, I prefer having the servo arm out in the wind for simplicity of setting up the control surface neutrals.
On the 60, there's sufficient depth at the rib to permit having all the servo except for the arm under covering.
I've never tinted anything, maybe the cars guys at the LHS could advise..

bojangle

Best way I've found to tint the canopy is with Rit Dye. Here is what you need. First of all an old pair of rubber gloves, a box of Rit Black dye for a gray canopy, or Blue, whatever you want. An old pot or pan big enough for the canopy. Add enough water to immerse the canopy completely, heat the water and add about 1/4 package of dye. Don't get the water too hot, or you will distort the canopy. Clean the canopy with soapy water to get off any oil residue or fingerprints. Immerse the canopy and keep it moving around, check it often for the right color. When it's about right, rinse it under the faucet and dry it with paper towel. (Don't make a mess in the kitchen lol)

I dyed a canopy for a Kaos almost completely black, it was perfect but I got the water too hot and it curled out of shape. I was able to use it though. I tried another canopy and it wouldn't take the dye very well. Varied types of plastics take the dye different. If you can, take a scrap piece and practice first.

Some just spray paint the inside with black or blue, whatever. It's your choice. But if you plan to have a "pilot", then the dye method is great. I don't like clear canopies, so I always tint them.

BO

dabigboy

Actually I could probably just run a couple hardware beams (or laminated pieces of ply) from the spar to the leading edge, rather than trying to match the ribs in ply, hmmmm.........might be stronger too.

Thanks for the tip bojangle.........the dye idea seems like it would provide a nice even tint across the whole canopy. Not sure what material this is though. I do need to keep it transparent. Might try the overspray idea on some other clear plastic object before trying to dye it, we'll see.............

If anyone's interested, here's a side-view I whipped up from a pic of my Tiger, showing the new colors.......

http://rtccom.net/~mattb/pics/tiger_side.jpg

The wings and horizontal stabilizer have the same stripe scheme on the tips as what you see on the vertical stabilizer in that pic. I plan on doing the graphics in Paint Shop Pro and printing them on a transparency, then sticking them onto the plane with clear monokote. Now that I've got the colors figured out I'm really psyched! This thing is gonna look nice.....................................

-Matt Bailey