Kyosho 40 Spitfire II Conversion - RC Groups
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Jul 06, 2003, 09:39 AM
Involuntary Beta Tester

Kyosho 40 Spitfire II Conversion


My first Kyosho 40 sized Spitfire was such a success for me I decided to convert another one after I lost the first last week after a dumb accident; the wrong model set on my TX.

I'm not going to take many photos for this thread since I will use my first thread as a guide for myself

https://www.rcgroups.com/forums/show...ghlight=Kyosho

Looking at how I contructed the landing gear modification I hope to improve on it during this conversion.

The new model will be powered by the same "Merlin" B50 10L, 5.2:1 and 14x10 prop but the batteries will be exclusivly Lipos, Thunderpower 5s4p pack, actually a 3s4p and 2s4p wired serially.

I weighed the fuslage, wings tail pieces and compared them to the first Spit weights

Spit 1
Fuselage 12.1
Rt Wing 10.4
Lf Wing 10.8
Tail 3.2
Cowl 1.2
Total 37.7 ozs

Spit 2
Fuselage 14.1
Rt Wing 9.3
Lt Wing 9.6
Tail 4.1
Cow 1.3
Total 38.4

Spit II is .7 oz heavier.

The real shock is the tail pieces, 1 oz heavier and the fuselage 2 ozs heavier. Luckily the wings came in an ounce lighter each to help offset the tail and fuselage.

I guess that's common with ARFs to have a weight deviation.

I don't know where I can reduce any weight easily.

I've got my build room cleaned up from the Seduction build and added an additional 6' table.

Here we go again.
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Jul 06, 2003, 09:51 AM
Involuntary Beta Tester
An additional item I ordered from Tower was a Robart variable rate valve. I thought it would be cool to be able to accurately adjust the retracts each way but experimenting with this valve last night I found it really isn't designed for Spring Air retracts. Robart retracts have two lines to each wheel cylinder; one for the retract cycle and then other to extend the gear while Spring Air have only one air line connected to each wheel cylinder. Robart does have downloadable instructions for Spring Air applications

With this Robart valve you have to plug one outlet and use the remaining. You can adust the rate of air exhast for the down cycle using the needle valve but on the retract cycle you still have to use 1/8" wheel collars to adjust the rate.

It is also heavier and larger than the Spring Air valve. The Spring Air valve is .2 oz and the Robart is about .6oz. After comparing the two valves last night I stick with the Spring Air valve.

One thing I like about the Robart valve is it's smooth and would appear not to require so much servo strenth as the Spring Air valve.

If anyone needs this Robart valve for a Robart retract application I'm willing to sell it for $20 (normally $24 at Tower, $26 at the local HS).
Jul 12, 2003, 05:25 PM
Involuntary Beta Tester
I've been working on the landing gear mod over this last week.

Here the wings are butted together showing the cutouts. Notice I cut out retangle. The weight of the wings is 8.6 and 8.3 oz. Chopping out the mounts took out about an oz and the parts I putting in only weigh .7 oz. I saved 1/2 oz.

I pretty much used the same procedure to cut out the wheel holes as in the previous thread on my first Spitfire.
Jul 12, 2003, 05:27 PM
Involuntary Beta Tester
Here is a closeup of one of the landing gear wheels. I put two layers of masking tape to try to protect the edges around the well as I test fit parts.
Jul 12, 2003, 05:32 PM
Involuntary Beta Tester
Here are the parts that make up the new landing gear mounting system for one wing. I little different design.

The main rib is light ply and has the spruce supports as before. Then the two mounting plates for the gear plates.

The rectangle and short square piece is for supporting the new rib against the main spar sheeting and the LE of the new rib to the LE.

The last piece fits into the lightening hole of the existing rib.

The small holes are for the retract hose.
Jul 12, 2003, 05:35 PM
Involuntary Beta Tester
This shows the new rib inserted under the sheeting with the ply main spar support between the existing rib and the new rib. The small spruce sqaure is between the LE of the ribs.
Jul 12, 2003, 05:37 PM
Involuntary Beta Tester
The light ply piece is inserted into the lightening hold of the existing rib. This will support the mounting blocks. I'll have to cut a slot for the landing gear to clear and the small hole may be part of the cut.

Next I'll glue these pieces in with epoxy.
Jul 12, 2003, 06:02 PM
Registered User
Gordon's Avatar
Hi Kelvin

The EJF mini retracts are little beauties, and being air up-down will work using the Robart air valve. I have 2 tri-gear sets destined for 90mm EDF projects.

EJF website has details.

Gordon
Jul 12, 2003, 07:50 PM
Visitor from Reality
Hi Kelvin
Good luck with #2. You'll do fine.

I know the BARF lobby will be on me all over, but why not tear off the kitchen shelf covering, make lighter tailfeathers and re-cover the lot in Monokote? The work you put into the first one, you'd be hardly behind the game recovering her, plus you could go into the wing properly and make sure your retracts will stay put.

Positive side - at least you have no excuse for sending this one off with a pilot

BIG HINT - Make sure you can borrow the August and October issues of QEFI

Regards

Dereck
Jul 12, 2003, 10:45 PM
Involuntary Beta Tester
Quote:
Originally posted by Gordon
Hi Kelvin

The EJF mini retracts are little beauties, and being air up-down will work using the Robart air valve. I have 2 tri-gear sets destined for 90mm EDF projects.

EJF website has details.

Gordon
Gordon,

How much do they weigh?

How do they compare size wise with the Spring Air 603s, such as flange width and length?

Kelvin
Last edited by kelvin; Jul 12, 2003 at 10:51 PM.
Jul 12, 2003, 10:50 PM
Involuntary Beta Tester
Quote:
Originally posted by Dereck
Hi Kelvin
Good luck with #2. You'll do fine.

I know the BARF lobby will be on me all over, but why not tear off the kitchen shelf covering, make lighter tailfeathers and re-cover the lot in Monokote? The work you put into the first one, you'd be hardly behind the Regards

Dereck
You know I was tempted to do this but again the problem with the markings. I'd need to learn to make them off the computer. I don't have any drawing programs.

Is Monokote ( one of the heavier coverings I've read) that much lighter? I remember you saying I could save 6 ozs.

I'm pretty confident these landing gear mods will be better. First I've only used harder ply for the mounting plates. The first Spit had soft ply with a harder ply laminated to it.

I've epoxied the ribs in and have been working on the hatch. The hatch is cut and I've cut the end cap formers. Just need to reinforce the sides of the hatch and the fuse opening like before.

Thanks

Kelvin
Last edited by kelvin; Jul 13, 2003 at 08:12 AM.
Jul 13, 2003, 08:29 AM
FAA
FAA
Master Model Collector
FAA's Avatar
Great Job, once again, Kelvin

I agree with Dereck.

You should take the time and strip the sticky shelf paper off the aircraft ! It WILL fail on you sooner or later. Go on RC Universe and read about it.


Keep going !

Nick
Jul 13, 2003, 08:03 PM
Visitor from Reality
Kelvin
Try this - strip off the shelf paper, but carefully cut out the markings you can't repro in Monokote. Save them, recover the model, either stick the markings onto the Monokote or use them as patterns out of Mono sticky trim.

That would make reproducing the lettering a snip.

For the roundels, off to a craft shop and look up an "Olfa" circle cutter in their hobby knives section. A good craft shop will have a whole section of cutting thingies, and they aren't too expensive. My little Olfa cutter will do about a 3.8" radius circle, and there might be a bigger one if 8" dia. won't do it for you.

I make roundels by cutting out anullus (annulii ? ) starting from the base colour, with the centre spot being the only solid circle. Slop windex all over the covering to allow scooting the sticky stuff around some to place it precisely.

You might not be able to repro the 'kit' markings, but did the Japanese really research them to start with? I'd love to lose 5 - 6 oz if I was in your shoes...

Regards

Dereck
Jul 13, 2003, 09:24 PM
Eye Drather Beef Lying
ElectRick's Avatar

How light is too light?


With losing 6 oz. by recovering, you could go from "way overpowered" to "oh my God that's insanely overpowered", with the B50 Hacker.
Jul 13, 2003, 10:17 PM
Recruiter - 60 Amp Club
Ed Lyerly's Avatar
Kelvin,
Ask these folks (FAA, Dereck, ElectRick) if you go to all the trouble to recover the airframe .....and the savings turns out to be more like 2-3 oz than the 6 oz they are promising ......how much they are going to compensate you ($) for your trouble .
Ed


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