what about taking a SS60 and putting 3 os 40las on it???  One on the nose and one on each wing????

I laser cut the mods for making a stock Sportster into a twin. www.lasershortkits.com

I finally finished my Super Sportster 120 Twin. Two OS 61s and retracts. Wingspan is 80 inches and it weighs 14 pounds, the wing loading is 31 oz/sq ft.

It came out very tailheavy. I had to move the rear mounted elevator servos up to the wing saddle area and add 11 oz of batteries to the extreme nose.

Synced the engines this past weekend, but haven't flown it yet.

Jim

Sweet!!!

Looks good JR. Hope the test flight goes well!

Looks great..

But being so tail-heavy, that's amazing.

Hopefully it flys well.

P.S. I'm glad you recreated both the covering scheme for your plane, and the photo pose.

Hi Jim. What did you think about the .61s. Where they adequate for power or do you feel you could have used maybe a littel more?
Thank you,
Ken

Ken:

The performance on two .61s is better than a single with a 1.20. The twin is heavier than the single, so even though it is faster, it doesn't have quite the vertical that the single has. Still it will do BIG loops. I wouldn't want any more power and adding weight that close to the CG wouldn't help the balance much.

But the 65AX might give it a little extra pull and the 75AX is only 3 ounces heavier.

PM coming.

Jim

And he's wearing the same hat.

I just ordered the plans from RCM. This will be my first twin.

Greetings All - wake up, shaking up this thread, again(!)... Well, I scored a Super Sportster non-MKII today and my build juices are running to convert it to the twin. I already half of the power choice selected a NOS Thunder Tiger .25 Pro. I have want ads up here to find a match for it. The SS kit is already in the mail and I am binging on RCU references to this cool setup, getting ready for the build.

I found a gent here on RCU who scanned in EVERY ISSUE OF RCM from 1963 to 2005!!! and have appealed to him for copies of the Jan 1985 RCM article.
The plans are not available on outerzone, checked there already.
Peace,
Poughkeepsie Pete

How did you make out getting a scan of the original RCM article, BrightGarden?

If you're still looking, I can help since I have that issue of the magazine in my stash.

Since RCM has pretty much gone the way of the dodo for plans, does anyone out there have the plan for the 90/120 Super Sporsters kiciking around? Once had a kit for it and like an idiot, sold that off prior to copying the plans.

I too donated $20 to the folks at RCM, thinking I would get the Super Sportster plans. I finally gave up and built my own. I inverted the fuselage and made it a high wing with twin tails. It has a pair of OS FP40s that have been dieselized. I never did get a chance to fly it this year, but next spring for sure!

That plan is now available on outerzone.

LOTS of great plans on that website!!

Bill S>

Hello
There is still people the Super Sportster twin have built ?
I plan the reproduction with that plans of Outerzone for me.
I will milling the Parts to building the Supersportster Twin.
sorry for my bad english i can it unfortunately not better.

Greetings Bernd

Hello.

Hopefully this thread isn’t totally dead. I just acquired this airframe from a fellow modeler. Actually it was given to me. He didn’t know what it was and it turns out it’s a mostly built, SS40 twin. One thing I noticed is that it’s a heavy airframe with the nacelles adding a lot of weight. I’ll have to open them up to inspect/refresh the fuel tanks and hog out the balsa to try to shave off some weight. I have a few engine options, 25FX’s, 25fsr’s or 32fsr’s with the 32’s being my first choice. But I’m sure the 25’s would work well too.
Anyways, if someone is still out there feel free to chime in with comments, advise or just to say hi.

Hi, sorry to dissapoint you but I only flew my Sportster twin one time. I found it to be a very heavy for it's size basically a lead sled that was not fun to try and fly! It was hard to get enough speed to get it off the ground. Once it was flying, the high wing loading was evident. It was fast but hard to control. I was using 2 Fx32 motors. I pulled them when I got home to put into other projects. Imho, the wing is simply too small to carry the extra load of a second engine, narcelle, fuel tank and extra servo. I did make another twin from plans using 2 FX46 engines. The build took a long time to put together. It is also heavy but has a huge wing and control serfaces to handle the extra weight of two engines. It is amazing to fly! 😁 Hope this helps. Cheers!!

Good morning!

Well, this is a disappointing read. lol! However, I am not surprised. The airframe as you see it weighs in at just under 3 lbs. So a finished, rtf model would be at least twice the weight. I have been down this road with an old Kyosho P-40 arf designed for a 52 4 stroke. Decided to put a heavy Saito 65 in it. It flew nice but it had a pretty high wing load.

At least I don’t have anything into this yet. I think the nacelles are way over built.

Thanks for your input.

Ya, that guy that came up with that deseign said it flew with no issues. I wish he was at my field, we would have had a word!! 😡. Don't know if you are interested in building from plans. If you are, the RCM Twin Trainer plan # 724 is a fantastic flyer! It took me a lot of time to build but if you really want a twin, this one won't dissapoint! You can actually download the plans for free from the web. I have included a picture of one before it was covered. What you think??

Thanks for the idea Fastsky. I’m gonna put this on the back burner for now. I may revisit it sometime in the future. I have a NIB Hobbico Twinstar arf, GP profile P-38 and a Royal Partenavia P-68 in my stash. Think I’ll start with the Twinstar. I saw one fly at the field a few years ago. It wasn’t particularly fast but seemed to fly nice. It would look sharp with retracts.

Sounds like you have enough to keep you busy!😁 The reason the RCM trainer works is because of the wing deseign, it has a very thick high lift shape. On the twinstar, personally I would not go with retracts. The twins are heavier. The last thing you need is to have your plane hit a bump in the grass and then collapse or bend. I have seen some Twin stars fly at our field and they seem to be ok. What ever you go with, I am sure that you will have fun. Cheers! 😁

I think you’re right about the retracts. Just assemble per instructions and enjoy!

Thanks for all your input.

Cheers!

Just another option for converting a kit. 4 Star 60 with a couple of LA .40s. Plenty of power but due to having clipped the wing one bay when it was still single engine it didn't really have as much wing as I would have liked. If I were doing it from scratch I would add an extra rib bay to each wing over stock. The wing loading wasn't any worse than a lot of warbirds but it lost some of its sport plane flavor.

Hey mgnostic, I’m glad you chimed in.

I picked up a 4*60 a couple of years ago off of FB mkt place. The guy was trying to convert it to electric and gave up on it. I picked it up real cheap but it is badly fuel soaked. Trying to dry it out with KR2 & heat with towels but this may be a perfect candidate for a twin conversion. It has a 79 inch wingspan with the added wingtips.
did you design the nacelles yourself or are there plans to do this somewhere?