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Sportsman Aviation F20 & retracts?

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Old 08-26-2005, 12:07 AM
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Endor
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Default Sportsman Aviation F20 & retracts?

Has anybody added retracts to the Sportsman Aviation F20 ARF, the one sold by Hobby People?

I'm contemplating it, but not sure if the wing is thick enough. Plus, I'm new to retract installation too, so perhaps a bad choice for a first attempt? []

Any help or words of wisdom is appreciated....
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Old 08-26-2005, 04:44 PM
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Default RE: Sportsman Aviation F20 & retracts?

IMHO the wing would be the least of your worry. There is not enough room in the nose for the front wheel.[:@]
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Old 08-26-2005, 04:59 PM
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Default RE: Sportsman Aviation F20 & retracts?

Dunno about room in the SA F-20 but if you use Pneumatics (Air) it will be easier to install and set-up! I recommend Spring-Air (as they are designed to come down!)

Just run a foot of air tube to each side, throw the air bottle somewhere, install a switch/valve on a mini-servo and off you go!

A Propjet with fixed gear is like a P-51 with a 2 stroke- It'll work, but yuck!
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Old 08-26-2005, 07:19 PM
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Default RE: Sportsman Aviation F20 & retracts?

Play fair man its only a .40 size. I am in the process of putting mine back togeather and considered doing it but just too tight a squeeze.
BTW I bent the crank on my beloved MVVS .45.[:@] Got a new one coming from Morris. Have you ever looked at thier Tommy Hawk?
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Old 08-26-2005, 07:58 PM
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Default RE: Sportsman Aviation F20 & retracts?

Here are a few pics of the nose. If it folded forward, maybe. But back - not gonna happen.
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Old 08-26-2005, 10:19 PM
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Default RE: Sportsman Aviation F20 & retracts?

Vic- I know I have a Patriot ARF with fixed gear.... But I encourage others to take the extra step!

Looks like there is room to me, you place the nose retract right behind the firewall and it folds back towards the wing... Lots of room--

Are the MVVS and the F-20 nose damage related? [X(] I know you love that MVVS-

Oh yeah, the Tomahawk looks great but isn't it like $300+ bucks?
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Old 08-26-2005, 11:44 PM
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Default RE: Sportsman Aviation F20 & retracts?

Are the MVVS and the F-20 nose damage related? I know you love that MVVS-
Yea, first stinkin sorte. [&:] Crummy piloting if I do say so myself. I owe it to the plane to get it back in the air. I was so sick about the whole thing I didn't take a pick. I fear there will be more weight in glue than covering tho. I am working on this and the CM F-16 at the same time. I also picked up another Kangke for a buck twenty a month ago. Are you trying to tell me to start working on the Pat? It looks like I will be the pappa of a GP F-15 in a month or so.

The retracts will fit fine in the wing but gawd awful tight in the nose, the fuel tank gets close. If you ran 6 oz maybe, but I would rather fly for about 10 min or so.
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Old 08-28-2005, 12:25 AM
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Default RE: Sportsman Aviation F20 & retracts?

Ohhhh! Wow good hangar going GP F-15 eh? You not happy about it?

When using retracts up front, you use a 2 oz. hopper tank (leaving room for the nose gear) and keep the main tank (8/10 oz.) back towards the wing bay-

If you have not had a prop-jet with retracts, it is worth it! Oh, and it has less drag

Keep us posted!
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Old 08-31-2005, 06:31 PM
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Default RE: Sportsman Aviation F20 & retracts?

Thanks for all the replies!

A friend of mine has the F20, so after reading vicman's comments I looked at it more closely. You are correct... the front wheel is the kicker, and it would be a tight fit due to the tank. And here I was worried about the wings... [X(]

And going forwards would likely interfere with the cowling/motor mounts.... although that may be able to be worked around easier than the tank.

If that area were only a bit wider, could go with a fat and short tank versus the roundish tank provided. I have a tank from a Modeltech Magic Extra that may do the trick... kinda square.

Now, on ARFs that come with retracts pre-installed, they provide some plastic inserts that glue into the bay to hold the wheel when retracted. Any ideas on how that is handled when adding them after the fact? Again, perhaps a silly question but remember I've never installed retracts before...
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Old 08-31-2005, 10:09 PM
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Default RE: Sportsman Aviation F20 & retracts?

I would use the bottom of plastic cups as the retract wells--- Seems crude but it'll work

Remember the hopper tank- leaves you plenty of room up front--
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Old 09-01-2005, 07:44 AM
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Default RE: Sportsman Aviation F20 & retracts?

When you go buy your wheels keep the blister pack they come in to use as a well.

James, Your killing me man! I had a good run going to get the F-20 back in the air soon and now I gotta stop and think about how to do the hopper tank mod.[:@] Can you give me a little more education on how that works? [8D]
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Old 09-01-2005, 01:51 PM
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Default RE: Sportsman Aviation F20 & retracts?

Just a thought on this one

The main gear installation (air) is not difficult. The nose gear is the issue.

Consider, that the nose gear does not have to 100% retract into the fuselage If that is acceptable, then you have a fairly simple solution.

quick sketch attached
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Old 09-01-2005, 04:26 PM
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Default RE: Sportsman Aviation F20 & retracts?

I hear you Bob, but MAJOR surgery here. You would need to move two bulkheads around even to leave part of the wheel hanging out.
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Old 09-01-2005, 09:41 PM
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Default RE: Sportsman Aviation F20 & retracts?

I guess what I was thinking here, is mount the nose gear flush with the bottom of the fuselage (or close). U-shaped plywood mounting plate replaces part of the bottom nose skin. Similar to a wing installation. Maybe trim the existing nose gear mounting bulkhead lower section to clear the air cylinder. The strut would retract up no more than the thickness of the lower skin. Wheel retracts into the wing belly pan and into the wing a bit.

The idea is basically to do a main gear 'wing' installation in the nose. Except that the wheel 'vertical'. Exposed wheel is what ever falls out of remaining space. You can cut into the first 2-3 inches of the wing at the LE there to make a wheel well.
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Old 09-02-2005, 09:00 PM
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Default RE: Sportsman Aviation F20 & retracts?

I hate you guys![:@] I was making great headway to get this thing back in the sky now I gotta figure out how I am going to make this work. How much lead in the tail will be too much to be worth it? I already have about 8oz in the tailcone.[:'(] What if I cut about .5 off the nose? The stupid cowel didn't fit too well anyway.

Think think think.[sm=idea.gif]
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Old 09-02-2005, 09:03 PM
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Default RE: Sportsman Aviation F20 & retracts?

8 oz.? Maybe switch to an OS-25FX to save weight up front?
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Old 09-02-2005, 09:11 PM
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Default RE: Sportsman Aviation F20 & retracts?

LOL the one I take out of the Miss LA so we can trade?
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Old 09-06-2005, 10:32 AM
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Default RE: Sportsman Aviation F20 & retracts?

Maybe skip the regular engine mount - use a backplate mount. That will move your engine aft at least 3/8" (as long as you are going to build a new front end/cowl for it)
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