She's back

She can be rebuilt

After speaking to Paul @nitro yesterday he described my plane's damage as "a flesh wound". I was surprised, but I did persist in trying to put her back together. I had some time on my hands yesterday for various reasons and so poked along for much of the day.

The first problem was the two forward bulkheads being smashed by a combination of the engine mount being torn out, and Mr LiPo teaching a lesson on the rules of inertia. I started reconstructing the foremost bulkhead using the bits of balsa I collected at the scene.



Here's the forward bulkhead after I had pressed a few bits of balsa back in. Note, the balsa sheeting and framing in this part was never seriously damaged. My main concern was getting the thrust angle right.

The front bulkhead pressed back together pretty well from pieces and was secured with thin CA.

However, the rear of the front two bulkheads was more badly damaged, and I couldn't find all the pieces (although I was sure I collected *everything* at the field. Anyway, before I did any work she looked like this:



Unable to successfully assemble the parts I had for this bulkhead I took a different approach. My main problem here was building a space for the rear part of the engine mount to connect to. By using the parts I had I was able to measure approximately where the mounting point should be (the RV4 has right and down angle on engine thrust).

Rather than try and rebuild the whole bulkhead - given it was still strong as it stood, I used two long pieces of balsa running vertically between the bits of wood that still existed in the bulkhead and the correct width for the engine, allowing for the offset. These were secured with thin CA. Two much shorter pieces then crossed these spars horizontally giving the "box" to secure the rear of the engine mount in. Once again, these pieces were slightly above the whole in the front bulkhead to allow for the down thrust angle.



Of course the cowling was smashed, but nothing but a little sticky tape and plastic model airplane glue couldn't fix.

The stringers where resecured using thin CA. The top string was augmented by the presence of the canopy ply/velco connectors, which meant it all joined together quite strongly. The joint was reinforced by using bits of balsa between other parts of the frame. The spars that support the battery tray also came away (with the battery tray), and so these where put back in place and secured using thin CA.

She has been rebuilt

So, here she is at Curtin Oval this morning:



The Flight

Well, it was a bit of a model plane regatta. I was hoping a mate might come down but no doubt real world matters interferred. I took 4 planes - all 4 that are servicable. The RV4, The Ele-bee, The Zero, and the Electrafun XP. The 3 extras where to give me some flying if the worst happened.

The RV4 was on a new prop today - an 8x4 - a better fit for the towerpro brushless according to the Internet.

Before the RV4 flight I double checked all the control throws and neutral positions (as well as the usual range check etc). I noticed she had a little up elevator dialed in, but assumed I put that there on purpose previously. I gave her a little throttle to get her moving. As she started to get airborne she dipped a little to the left - oh crap - not again. Full power, and elevator, and a little right airleron. She screamed up to 15 metres. Safe for the moment.

Throttle back to about 40%. Plane is still climbing Remember the elevators and give her three clicks down elevator. Still climbing. Another two clicks - settled. She is rolling to the left. Couple of clicks right elevator - flying straight.

Now I actually notice how much faster she is with the 8x4. Frightening fast really - even at 1/3 throttle.

Apart from climbing she seems to fly straight and level at 1/3 throttle or WOT - good news - I have the thrust angle near enough.

I put her through one loop. The rest is just flying backwards and forwards. I can't figure out whether she is flying as well as last time, or whether I am just nervous, but she doesn't feel quite right. But still okay.

I try to bring her in to land. Flaps on. She pitches the nose down - too much, and after one or two failed approaches I decide on a no flaps landing, even though she is fast.

On the first real landing I get a wheel on the ground but she pulls up as I was flaring, I wave off and power up to go around.

Second approach is better. She touches down moving quite fast. I accidentally put her back into the air with up elevator (to hold the nose down and stop a nose over). She comes up abit, and from about 6 inches up stalls and lands a little awkwardly and noses over. However, no damage, and she is down.

Things to do

I'm going to try and dial in some elevator compensation for the flaps. My radio can do it, and the way she pitches forward with flaps is a little disconcerting.

I'm not sure I have the rudder right, and have a feeling that is some part of the "unease" of her flying.

Otherwise, very happy with her second flight. In a lot of ways I preferred the 9x4.7 - high thrust but lower speed - she just handled like she was on rails. But the 8x4 is a better match for the engine - it actually gives me full throttle play and jee she is quick at WOT.

Other News

The Zero has been upgraded to a 11.1v 800mAh battery. I checked yesterday, and it fits the GWS Zero battery compartment very snugly (so snugly I looped a piece of string round it so I could pull it out). This has given the Zero a lot more poke.

This is the first stage of Zero upgrade project. The next is a little brushless engine (yes, she was on brushed today), but that may have to wait a little bit. So current setup is 8x6 prop on GWS EPS400C BB C Gearing with 11.1 800mAh 20C Battery. Flight times are unlikely to be much shorter than the on the venom 7.4 1250mAh battery - less mAh, but I can draw a lot less current to achieve enough power due to higher voltage - of course with the extra juice I can burn the power much more quickly if I wish.

She had pretty good vertical performance actually - I was surprised.
Anyway, more on that later.