GaryHarris

I have an O.S. FS .30 with nothing to hang it on and I can't seem to find an airframe I like for it. I am currently building a 4*40 and got to thinking I could bash enough weight off a kit and be able to fly it with that little .30 Looking at this pic I'm thinking of building it as a flat top. No turtle deck, just a flat balsa top. Remove two wing bays and using my Bridgeport mill at work, mill out some lightening holes in the fuse sides forward of the wing saddle.

Maybe some 30% nitro and ultra leightweight landing gear. I think I can get it down to 3 3/4 pounds.

Think it can be done?

ChuckW

The 4-star has pretty light wing loading already so it might work just fine a little lighter with the small engine. It won't be a powerhouse but it might fly. You could also just have the plans reduce or trace each part and reduce them. This would give a smaller overall airplane. The design is fairly simple so cutting all the parts for a scratch build would be fairly easy. maybe even use balsa for the fuse sides instead of ply.

KitBuilder

The FS 30 is the equivalent of say a .20 two stroke? Even with the light wing loading that is pushing it. Be sure there isn't any wind [sm=what_smile.gif]

w8ye

My Feedback: (16)

Have the plans reduced at the print shop to 49-50" wing span or to around 83%

That 3 1/2 pounds would be a majic number

Hawkeye

My Feedback: (27)

Do you really need a Bridgeport to cut lightening holes? Seems a Dremel would work just fine.
...Steve

GaryHarris

If I reduced the drawings, wouldn't I have to downsize the thickness of the lumber in essence, scratch building?

GaryHarris

The idea is do a kitbash that kas never been done before. Yea I know I would be pushing the limits of wing loading and power, but I think I can pull it off with enough planning. [:-]

GaryHarris

I wouldn't, no. But I have one, so why not? Plus I can do a much cleaner job with the mill since I plan on covering the fuse with a lightweight, transparent covering. Of course for the wing, Ill have to use something heavier and stronger.

w8ye

My Feedback: (16)

You would use the next smaller size wood, It works out pretty well when you get used to doing it.

I have a couple friends that have made Robinhoods of every size imagionable by reducing Robinhood 99 plans

I have a Robinhood 80 made this way and it is hard to tell from a factory 80 kit

Bonified Wingnut

Hey, Under 4 lbs it will fly. I have a Pheonix models Sonic low wing with a Magnum 30 4 stroke in it. Its a dog but it is fun to fly. It is Over 4 lbs dry or close to it. Its so quiet it's almost like flying electric. I do knife edges and loops with it. Just not Low and not two in a row. That 4 star has to have more wing than my Sonic.
The sonic is on the far right.

Good Luck.

GaryHarris

Funny you mention it, but I had bought the high winged Sonic just for that engine. Two issues came up though. Allthough they say you can use standard size servos, mine wouldnt. The airelon servos and control rod hit the other servos. Arghh. [:'(]

The other issue was the covering needed shrinking. Ooop! I needed room and I eventually tossed the Sonic out.

I bought the OS FS .30 hoping I could easily find a plane for it. The PT .20 I first bought turned out to be a box of twisted heavy lumber which I never finished. The Eaglet 50 ended up weighing 5 lbs and flew like an under powered turd.

However, my new 4*40 came in at 5 lbs even and will go unlimited with a Magnum .52 four stroke and flys like a dream! I can pull this off. Ill do it during building season which is summer here. lol

carrellh

You'll save around 5 ounces in engine weight compared to the 52. You might be able to get the total weight under 4 pounds. If you can, post a few pictures of the build.

frenchie79

Gary-I too "had to have" the OS 30 with no plane. A friend of mine suggested the goldberg "Freedom 20", so i built it, and it is the perfect plane for the engine. Even though it's a high wing, it is quite a performer. Perfect Lawn chair plane, landings are fun coming down on two wheels. Power is plenty with great vertical perfomance. Just an idea-good luck.

twn

With 30% nitro it will be a rocket. Put a perry pump on it too. That will add a bit more power by supplying a bit more pressure, you will have to play with the pump pressure and engine low needle. I'm running a pumped saito 100 on 30% heli in my 7.3 lbs gp extra 300s and the vertical is completly unlimited. With 15% nitro the extra sux but WOW what a differance going to 30% made. I also had to go to a 15-6 prop to keep the rpm down (up from a 14-6) With the 15-6 the rpm tops 10,000 on the ground so in the air probably 12000-13000. My imac buddy threw everything he had at her and the extra did his entire routine, including rolling loops. If you want to see what kind of flying he did I'll post a vid of one of his routines if u like.

w8ye

My Feedback: (16)

We will always watch a vid

twn

This is him flying his Extra 330 3w 212cc 44%. This thing is insane. I'm a bit over 260lbs and it pulled me across the ground with ease. We have fun at events where we will pic a poor unsuspecting person and get him to help hold it back when starting it. One on one side up against the windshield and the fin. One on the other. Give a good lesson on how to hold it back when starting. I will let loose a bit (but still hang on, to keep it safe) when my buddy revs her up so the other guy gets a good 70-80% of the pull. he he The remarks are great after. The look on his face is priceless. The air pressure through the jet stream keeps u from breathing. lol

The best I ever saw, I personally watched him with his 35% Extra 300 (comp-arf) come in about 80-100 mph in low over the runway bleeding off a bit of airspeed and do a reverse wall into a hover where he scrapes the runway with the rudder. Absolutely insane! You could hear the slap when he hit the wall. I was just expecting a low fast inverted pass. What a shock! His dad was pattern champion back in the day.

[youtube]http://www.youtube.com/watch?v=RYwe6IC5nrI[/youtube]

The dude that did the film cut out a lot of his flight. Like the rolling loops, including a loop and circle that consisted of one roll through each.

w8ye

My Feedback: (16)

I can not say that I've ever heard that much prop BUZZ in a model before