Here is a preview of my next project. Approximate length is 100cm with a 63 cm wingspan. I'm thinkin Russian.

Finished construction with Prototype 8 pusher setup. Alot of changes between the last one and this one. Further refinements will be made before production phase but this one will fly. The flex in the wings and the tail is, for the most part, completely gone. All up weight is 18oz. The only reason its so heavy is because I had to add a reasnobly high ammount of weight to the nose(4 ozish) to counter the weight of the motor and electronics in the back. So you could run a really heavy battery on this A-10 and it would take it just fine.

Maiden tommorow. Also looking forward to doing two puller props on the front of the nacelles. If the performance is significant I might increase the scale of the A-10 again so its wing loading isn't so high with two motors and make it a mainly dual power set up. I will cross that bridge when I come to it.

Just completed the concept render for Prototype 8. The new model includes a thicker wing, smaller nacelles, additional reinforcement in the tail, and most importantly, some cool text on the concept render.

After speaking with a veteran builder/designer of foamies new life was brought to the single engine pusher concept. The final production A-10 will have a choice of a single or dual power set up but for now I am going to strive for a single engine power set up for the sake of simplicity. A dual layer wing has been added to the design; while the wing is relatively complicated for a foamy set up I feel it is needed to reach the goal of having a more rugged, crash resistent aircraft. Not only that but the wing has an airfoil on it to produce lift, an almost necessity for this design as the fuselage has almost no underbelly for added lift.

Also, since I am still having problems with the wings I am going to put carbon fiber reinforcement through them as well as carbon fiber reinforcement along the fuselage in key points to prevent the twisting from the torque of the motor. The straight carbon fiber rod through the wing should finally provide that support that is needed with this design.

The current wing area is about a total of 2 sq ft. With those numbers, the final weight of single motor A-10 should be in the nighborhood of 14 oz, giving it a wing loading of 7 oz per square foot. However, with the dual power set up it appears as though the total weight will be more like 20 oz, giving it a wing loading of 10 oz per square foot. It might actually work ideally this time.

Taxied it around a bit and tried to lift it into the air a few feet here and there and the wings are STILL flexing. I think I have found the culprit and thankfully its not going to require a full rebuild. Just the wings. I also determined that a pusher prop A-10 is a bad idea. The motor being mounted on the back creates several problems with the CG not to mention compounding the stresses across the rear part of the A-10, requiring several structural reinforcements that are really not reasonable. I am going to order 2 new motors/esc's that aren't welgards. Probably going to order two 370 class motors/esc's. These can be handled better by a single battery and are designed for aircraft up to 12 OZ, normally offering around 10 oz of thrust. Two of those offer 20 oz of thrust, which will be about the finished wight of the A-10 with 2 motors on it. I think I found out why nobody has came out with an easy to make foamy A-10 hehe.

Prototype 7 is complete...for the most part. I havn't spent any time on the nacelles because they take a long while to do and don't effect flight performance that much. Essentially I just want to get this thing to fly nicely at this point. Maiden planned for this afternoon.

A-10 Prototype 6 had a successful flight! However, due to my stupidity and willingness to NOT wait for a day with an average wind speed below 16 mph for a maiden it got destroyed. When I tried to land it to make adjustments there was that super lucky gust of wind again that nicely placed my A-10 onto the ground. And when I say "nicely" placed I mean it dropped, wing first, onto the gravel below and tore the model apart. I stripped all of my equipment off and threw it away. Prototype 7 with further revisions will be constructed by the end of the week and hopefully a successful maiden will take place.

Completed repairs to the A-10 Prototype 6 as well as the changes to the tail. I decided not to take the time to repair the wing pods as there function to the flight is really minimal...and the little pieces of foam I put on the side of the fuse really tells you how much concern I have for the cosmetic appearance of this model for the time. Only a prototype. As long my repairs hold together fine, maiden will be planned for this afternoon. (weather permitting)

Got hasty with the maiden today. Even though I looked up at the rain clouds and felt the 10 MPH wind across my face and hair. Even though there was that gut feeling that said "Gotta wait man" I throttled up and threw it solid into the wind. It climbed up and out then a gust hit it JUST the right way. It immediately dropped to the hard concrete below. Thus the results: Good news is my built in breaking point worked PERFECTLY at cushioning the blow and a repair will be quick and cheap. Also, as Dave Powers suggested, I will be making modifications to the rear tail to include an elevator with nearly three times the surface area to guarantee good, solid control in the air. Prototype 6 is NOT getting retired, just modified and fixed up for a second attempt on a non gusty day.

Prototype 6 is now complete and the total weight before additional components(foam only) was 4 oz. The finished, ready to fly weight is 14 oz. This gives the model a wing loading of about 7 oz per square foot, pretty good by my inexperienced standards. My radio has been programmed for the airplane and the batteries are charged. All ground tests wielded positive results including a glide test with a total aircraft weight of one pound. The wings DID sag slightly but added support offered by bamboo sticks made the all important difference. Also, a thrust test with my power setup showed a thrust capacity of about 18 oz. Maiden flight tomorrow afternoon, expecting good results.

Prototype 6 has been designed and I am now working on construction. Hopefully this one will fly right.

I actually tried to fly it today. The wings warped up into a "U" shape from their span so I have two options at this point: I can't lower the weight any further or the CG will shift so here are the only 2:
1) Spend an unreasonable ammount of time and/or resources making a FULL scale wing to handle the weight
2) Scale the entire model down so it can better handle the wingspan.

I think I am gonna go ahead and go with Number 2. To prevent this from happening again the new scale is going to be exactly 1/2 that of the airplane before. Good news is all the building testing is done so all I have to do is modify the plans for the new scale and start building again.

The total weight of prototype 4, foam alone, was 10 OZ. Considering the new one is going to be using a lighter glue and less glue I will go ahead and assume its going to be 10 OZ, even though it will probably be less. The weight of all components is 11 OZ without the classified payload and 15 OZ with it. What that means is even with the payload, my total weight should not exceed 25 OZ, batteries and all. That drops me within the target wing loading of 10 OZ per square foot.

The 5th prototype is now being assembled and will be made this time with intention of powered flight. Just about all the problems have been solved and it seems ready to get up and out. Should have main construction complete by Monday, May 5th with maiden planned by Wed, May 7th. I will put up photographs of the finished model before the maiden and hopefully have a video of it up by the end of the week. Project nearing completion!

Further refinement made to the aft and front of the engine nacelles. Since I am mounting the actual electric motors on the front or back of the engine nacelles I spent a while doing some thrust line tests on the model and couldn't help but notice that the back of the engine nacelles of the actual A-10 tilt the thrust from the engines to where it is even with the centerline of the aircraft. So to prevent my model from being overcomplicated the slots for the motors have been tilted to accommodate the tilt of the nacelles to bring the thrust line even with the centerline of the aircraft. One more little thing down.

Got a scale today and weighed my A-10 (Prototype 4). Looks like its at 10 OZ and I will probably be able to keep the total weight of the aircraft well below 25 ounces! Thats just short of 2 pounds! That would give it a wing loading of less than 10 ounces per square inch of wing area! Even with the planned payload strapped on(new weight of 8 ounces), that would bring the total weight of the aircraft up to no more than 35 ounces, just over 2 pounds!

Prototype 3 has been retired and prototype 4 has been constructed. I would put up pictures but the design has not changed enough to make a visual difference. Equipment to get this airborne is in the mail as I finalize everything with prototype 5. The following improvements will be made to prototype 5:

1) Further simplified construction. Total pieces have gone down from 48 to 33. While 33 is still a big number, you have to remember this is like making a paper airplane with a 2 foot wingspan. It IS possible to make a paper airplane that big, but paper is not thick OR strong enough to cope with that kind of wingspan realistically. So many steps had to be taken in the design to make sure the plane wouldn't flex too much in the air to guarantee a solid flight performance.

2) Added several notches. While notches in the design make the foam a bit more of a head ache to cut out the model stays together a lot better when 2 pieces come together with something more than glue. The notch system also helps simplify the construction because you aren't going to try to glue something to an airplane if it doesn't fit right.

3) Extended bottom wing area. I extended the bottom wing section part for two reasons: The extended forward section crosses the old forward breaking point in the fuselage. What this does is it moves the breaking point to the new location far forward of the wings and also greatly increases the strength of the front of the fuse due to the second reason: The new extended peice now has a few new sets of notches to help make sure everything lines up like its supposed to. This new bottom area will also make a wonderful spot for a battery.

4) Further refined engines. While the current set up on the engines is satisfactory, I want them to be rock solid because I will be mounting engines to them and putting alot of torque through that point on the airframe.

Prototype 5 under construction now. I'll have pictures and before long videos of the maiden.

Here are the breaking points on the aircraft. It being completely disassembled you can see where I designed in the spots for it to break apart. These aren't built to where the model comes apart in the sky while your doing a stressful maneuver, but spots that are designed to break apart in the case of a crash because they aren't as strong as the areas around them.

Well prototype 3 was a very big success as far as ironing out some of the big problems the model has. However, I already have a list of improvements to be made to pave the way for prototype 4 before I say its time for powered flight.
1) While the issue with mounting the engines has been all but solved, I still don't like it 100% so improvements will be made to make the engine mounting alot easier and more impact resistant. For those folks who are worried about weight, I'm not actually going to add any components, just modify the way they are made and used.
2) The landing gear pods still need work. Everytime I build them they fit like a glove on the wing but a slight knock on the front and they get all messed up.
3) The gap in the wing that was created for the electronics inside the fuse has been made smaller. Stressing the wing showed that it was likely to compound a structural issue with the lower part below the wing causing it to want to break and tilt the wings forward as well as weaken that part of the model.
4) Servo placements! The plans are now made to accommodate HS-55 servos for control.
5) Additional reinforcement to the center wing area has been made to help solve the problem that I created when I changed the construction methods.

Many of these issues are rather small when it comes to model and probably really wouldn't be that big of a deal if I didn't solve them but as anal as I am this model has to be darn near perfect before I say it's done. This is the proverbial "ironing the problems out" portion of the design where I just target the little annoying things that have yet to be solved and find a solution.

The following problems that were experienced with prototype 1 and 2 have been fixed/modified:
1) The nose is now twice as strong as it was before as the reinforcing structure for the wings has been extended to the nose.
2) Completely redesigned the aft section between the wings and horizontal stabilizer. The flex that I described that was present in the earlier prototypes is now completely gone.
3) The new rear section also included a new mounting set up for the engines, this new setup has proven to be successful with a few stress tests so far.
4) The nacelles now round off nicely with the new method used.
5) The wings have been made thinner for two reasons: to help reduce drag and increase the top speed and to make the model look more scale
6) With the thinning of the wings, the entire horizontal cross section has been lowered. This adds stability and a more scale look to the model.
7) The wings and fuse are now made to separate to reveal a location for radio equipment and for easy transport
8) wing tips redesigned for simplicity and a more scale look
9) Pods below wings also redesigned to accommodate possible retractable landing gear
10) Horizontal stabilizer lowered to add stability and also to increase the scale look of the model.
11) Several smaller changes to help simplify the build.
12) Rudders have been reshaped to more scale look and to make them more effective.

I didn't really notice how unscale the previous prototypes looked until I made this...Continue Reading