Originally Posted by Truckracer

In my opinion, the 30 is nearly a perfect match for the CUB. I prefer the standoff mounts as it leaves the carb out in the open for easy adjust / linkage hookup, etc. Couple the 30 with something like a Zoar 19-6 prop and you have excellent vertical performance yet you can fly around all day just a few clicks off of idle for scale like flight.

The 20 will fly the plane just fine, the 30 just does a better job of it! As most people know, the DLE30 has a more manageable idle than the 20, as the 20 still comes with that funky Rcexl #4 ignition. You'll probably need the extra weight in the nose of the BUSA CUB anyway. Pitts style wrap around mufflers easily fit in the cowl with no modifications.

+1 The 30 is a perfect match. I wouldn't want any less power than the 30 has on this cub.

I have had a saito 120, an air hobbies 50cc twin, and an evolution 35 on busa 1/4 cubs. 35cc evolution is the best.. Buy the dle35... And put a turnbuckle across the top of the fuse to tied to the wing bolts to hold the fuse sides together...they are not strong at all in negative g situations...


And do yourself a favor and add flaps to it...

Originally Posted by 2walla

I have had a saito 120, an air hobbies 50cc twin, and an evolution 35 on busa 1/4 cubs. 35cc evolution is the best.. Buy the dle35... And put a turnbuckle across the top of the fuse to tied to the wing bolts to hold the fuse sides together...they are not strong at all in negative g situations...


And do yourself a favor and add flaps to it...

A wing tube with bolts through the bottom of the wing into the tube also solves the negative G problem. To say the least, the top of the cabin in a stock BUSA CUB is delicate at best! This also reduces the loading on the wing struts.

Originally Posted by Truckracer

A wing tube with bolts through the bottom of the wing into the tube also solves the negative G problem. To say the least, the top of the cabin in a stock BUSA CUB is delicate at best! This also reduces the loading on the wing struts.

Thanks for the advice, can you guys post pictures of the wing tube and turnbuckle mods referenced? Thanks

Mine has flown for many years with the original design. And if you want to scale the inside that tube will get in the way. Never had an issue and I fly the piss out of it

Hello, i'm new to anything that isn't arf and i am already confused about mounting the window frame to the 1/4 balsa cutout. do you cut the notches all the way through? Eh... I have a feeling i will be asking many more dumb questions

How did the CG come out.. Did you have to add weight to the front...

wow, nice work

digging this up from the grave. I noticed the op installed his servos in the tail for shorter linkage runs. Just wondering how the weights came out balance wise with the dle 30? I am building one right now and just purchased a dle 30 for it. Also wondering what is meant by adding strength to the upper fuse sides for negative g's
thanks
jeff

The only thing that holds the top of the fuse together is a piece of 1/4x1 glued between the two sides. Not a lot of support for negative g's. I have the elevetor servo aft in mine rudder servo is forward with pull pull. Balance will be fine with the 30.. i would add some carbon to the horizontal stab just for handling etc. I have seen one flutter and come apart that was built 100 percent from the plans.. I broke mine pulling it to the pits by the stab once.. it now has a couple of carbon rods full span of the stab.

Originally Posted by 2walla

The only thing that holds the top of the fuse together is a piece of 1/4x1 glued between the two sides. Not a lot of support for negative g's. I have the elevetor servo aft in mine rudder servo is forward with pull pull. Balance will be fine with the 30.. i would add some carbon to the horizontal stab just for handling etc. I have seen one flutter and come apart that was built 100 percent from the plans.. I broke mine pulling it to the pits by the stab once.. it now has a couple of carbon rods full span of the stab.

I read the above posts on strengthening the upper fuse area but didnt know how they meant to do it. I havent built the horizontal fin yet so I can incorporate some carbon fiber into the build. I appreciate the advise and would like to know how to strengthen the upper fuse area.
thanks
Jeff

on the forward wing bolts I used a piece of aluminum u channel cut off as a washer so the u was facing out they are drilled for a pin then a turnbuckle is place between them and snugged up. this transfers the load across the fuse vice thru it. most of the guys I fly cubs with have done this mod. and their planes are 15 plus years old and are flown pretty hard. lots of one wheel dragging the wing tip landings. I'd you don't mod it a 1/2 mistake drag the tip landing can be your last. . at a minimum I would do the stab. look at the birdcage area of the fuse and look at what's really holding the plane together when you do an outside loop. a piece or two of tri stock adds a lot of surface area for the glue. the turn buckle gives you the long term abuse margin.

the other mod is to move the strut attachments aft 1/4 to 1/2 aft on the fuselage. this keeps the access to the bolts free to access from the bottom. at the stock location they are hard to get at from either direction. if you do a doped or painted finish it will develop cracks/chips in the strut attachment area because of the access

Originally Posted by jjoos99

digging this up from the grave. I noticed the op installed his servos in the tail for shorter linkage runs. Just wondering how the weights came out balance wise with the dle 30? I am building one right now and just purchased a dle 30 for it. Also wondering what is meant by adding strength to the upper fuse sides for negative g's
thanks
jeff

I did use smaller servos in the tail. Balance is not an issue with the 30. The most interesting part is fitting all of the items up front as I wanted it all hidden so I could scale out the interior.

I also want to encourage strengthening the fuselage in the wing mount area. Remember, any negative "G"s will want to pull the wings away from the fuselage and there is minimal structure up there to sustain this stress. As mentioned earlier, I prefer to add a wing tube to slide the wings on as it makes installation so much easier than trying to hold the wing roots in place while juggling the screws into place. Bolts through the wing into the tube take most of the negative "G" pulling forces. The struts are still 100% structural though and with my mods, the wing tube only supports minimal flight loads. The struts do most of the work.

Built stock, one small landing mishap where you catch a wing tip on the ground will completely destroy the fuselage above the midline. Seen it happen several times with high wing designs. Built right, you can drag the wing tips as much as you want with one wheel landings and the only damage is worn covering on the tips.