I decided to scale up my Fun 51 plans. I have a plans built Fun 51 with a Magnum .52 4s that flys great. I have a twin Mustang P82 built from two Fun 51 kits and highly modified. Just could not resist having one just a touch larger for the Saito .82 and a set of mechanical retracts I pruchased new for a project that never took place. Have all of the parts laser cut and have started assembly. I will post a few pictures of my progress, should build quickly. Decided on a 51" wingspan, what else?

I haven't finished my Tower Fun 51 yet. But arter reading the forum, I sandwiched the two ply fuse halves together with a piece of Kevlar so the fuse should not break apart.

Hey BPS!!! good to see you again! well if anyone is the man to scale one up you are!!!!! I aquired a Fun 51 kit not too long ago it seems there are a few twin Uproars out there but not so many Fun 51 twins, you are the subject matter expert here!!! I am thinking you could borrow heavily from profile tecnology that is allready being used, a carbon fiber rod or rods in the main fuselage seems to be the trend right now. it will beef up the longitudinal strength and distribute the engine load throughout the airframe. Look at Swanys House profile airplanes, he is the go to modern tech guy on profiles and there are tons of build pics to give you an idea of how and where to put the CF rod. I will be watching this thread with anticipation as we are thinking of building giant Uproars.

I have flown the twin a lot and have found no need to stregthen the fuse. Mine is holding up just fine. My fuses are however made of a 4 ply laminate of 1/8" light ply from the nose to the leading edge of the wing. Then two plys of the 1/8" light ply to the trailing edge of the wing. Both smaller versions including the twin utilize the truss structure of 1/4" square balsa faced with 3/32" balsa sheet on both sides. This larger version will have the 4 ply 1/8" light ply to the trailing edge of the wing with a truss structure to the tail of 1/4" square balsa and then sheeted with 1/8" balsa both sides. The fuse is finished and I am starting on the wing. The retracts will be an added challenge. Pics to follow.

I now have the fuse ready to sand and the wing ready to add the leading and trailing edge sheeting. I will complete the retracts before adding the bottom leading edge sheeting. Around $100 in balsa and light plywood to build this plane. Thinking about blue monocoat with a yellow nose.

I just about have the wing construction finished. Installed the retract rails and when the epoxy dries then I can fit the retracts and servo. Retracts are mechanical and fit like a glove in the area just in front of the aileron servos. More later.

Hope the scaled up version flies better than the original.

[quote]ORIGINAL: WCB

Hope the scaled up version flies better than the original.
/quote]


I have the twin P82 built from two highly modified Fun 51 kits, a real stretch calling it a Twin Fun 51. I also have a plans built Fun 51 which flys great and is rapidly becoming my favorite sport plane. Once set up correctly I am impressed with the flying qualities of the little Fun 51. Just finished a plans built 33% BD8 this spring. Interestingly enough the Fun 51 flys a lot like the BD8. Both planes are short coupled and can be a handful until the correct amount of control throws and expo help are added.

My hope is the F51 Plus flys as good as the Fun 51. We will know in a few weeks. Maybe I should call this thing the F51" since the wingspan is 51", thoughts?

Thanks for the comments


More later.

Here is the larger Fun 51 inch wing span just about ready to cover. Retracts have been fitted and the airframe sanded smooth ready for the blue and white cover job pictured below.

Nice project! I also have the Fun 51 & it flies GREAT! I dont really see any issues with your scaled up model. The retracts are interesting tho.....Gene

I just about have this plane covered. I hope to start the assembly latter this weekend and get the bird ready for the radio. More pics to follow.

A couple of pictures of the plane in dress being assembled. another week or so to go!

Looking very good!

How did you make the 51P logo?

They are just adhesive vinyl graphics film. Gold numbers with black shadows. The gold is transfered onto the completed finish using a low tac transfer tape that looks a lot like masking tape. I use this tape for a variety of jobs. Once the letters or numbers are in place then the black shadows are slid in place using windex on the surface. Use a paper towel to squeeze out the windex under the decal and just let it dry for overnight. Smooth down the decal with finger pressure and clean the area with a little more windex and wala! I have a decal and tag business where I make industrial identification products for machinery and control panels. I also have my own laser. Makes life a little simpler! At least it would if the economy would pick up more.

Thanks, bps!

Your build made me dig mine out of the rafters, dust it off & fly it today....Gene

Sorry for the double picture post, computers & i dont get along....Gene

Nice looking plane Gene. This bird is a lot of fun for a $60 kit. My scaled up version should fly this week end unless something crazy happens. Then the next project is going to be a large scale airplane. Not sure which one, I have several plans and kits to do yet! I need to post more pics later today.

bps, thanks for the comments, i'm following along with your build and anxious to hear how she flies when your finished....Gene

I am finished! Maiden flight maybe this afternoon if the weather co-operates. Would have flown it yesterday but by the time I finished chores it was just to late and the weather was not all that good anyway. With a Saito .82 5 digital Futaba servos, with one Hitec retract servo and a NImI 6v 2a battery the plane tips the scales a touch over 6 pounds. With the battery moved as far rearward as possible I still had to add 1.75 oz of weight to the tail[:@][:'(][&o]. I just hate to add weight! A wise designer once advised me, " If you must add or change something, add simplicity and lightness"! Flight report to follow.

Nice looking model! Anxious to hear how it flies...Gene

Ran out of time today, Monday or Tuesday if the weather cooperates.

Flew the 51 last evening. The Saito .82 4S is plenty of power and pulls this plane straight up. Gear reatract function just adds to the fun. I do have one big problem though and it will need to be repaired this winter, ending the flying season for this bird. The joint where the fuse meets the wing developed a crack. I think this is mainly due to the vibration that the Saito creates, it is a bunch. Spinner, prop ballanced and rechecked. My fix will be to add 1/4" ply to both sides of the fuse back to the rear edge of the wing. That should stiffin things up considerably.

I am also considering moving the motor back an inch to help with ballance. I did have to add a touch of weight to the tail. With the extra ply on the nose I will need to add more tail weight. Looks like about an inch would do it.

The last modification I plan is to add a tube on the bottom of the fuse to carry the crackcase drain and exhaust. The Saito creates a bunch of mess along with all that power.

I plan on fireing the engineer on this project as soon as I complete these mods! He gets fired a lot.

Could you use the wing as a stiffener fot the fuse?

The fuse hole for the wing, combined with the distance to the engine, make the section that developed the crack the weakest point from the nose back.

If you could make a solid joint between the wing and the fuse, no additional reinforcement or cover work would be needed.

Just and idea.

Thanks for the suggestion. I think not though. This area was glued with epoxy, then a nice smooth fillet of epoxy was placed around the wing/fuse joint. The Saito just shakes the entire front of the fuse and the needle valve can become a blurr at just the correct throttle setting.

I already have the motor off and the doublers made for the front. Just a matter of stripping off the covering, grinding off the epoxy and glueing the new doublers in place.

Also found that an empty butane container will make a great expansion chamber for the exhaust system. This should collect the oils and deposit them out the bottom of the plane where they will do less damage. I will post pictures of my progress.

Thanks again for the suggestion