n00bs Gonna Build a Carden

[gareth.ky]

Power is provided by two 2300mah A123 packs that I built from a Dewalt 36v drill battery. Johnny Chimpo Brand Each pack has 16 gauge wire (Tower sells it) and connects to a Kodiak switch. From there prower goes over 16 gauge wire to the Rx. The right side switch also has a lead that powers the ignition. So one switch turns on the radio and the other turns on both the radio and the ignition. Because the Rx is visible its easy to see before takeoff if both switches are on, even if you cant see both sides of the airplane easily. I'll keep a close eye on how the packs drain and report back on the setup. Even of the right side pack drains faster than the left the failure mode is at worst a dead stick.

The battery packs had to be mounted out on the motor box. Its just where they had to be for balance. They had to be low down like that so the cowl would go on in 1 piece. I'm a little worried about all the weight in the airplane being so low down. The inverted engine, canister and batteries are all below the thrust line. I'll just have to wait and see how that works out.

The Rx, satellites, ignition and battery packs are all mounted on industrial velcro padded with foam rubber. The radio gear has masking tape on it so you don't have to glue directly to the gear. It's and idea I got from one of Quique's ARF manuals.

An I have photos I don't have comments for:

That's the CF tail tube. thw dowels are glued in the ends and then you drill into them for the mounting screws. Walt recommended that one.

The manual choke. Its got fuel tubing on it so it doesn't rattle around.

Final weight of the fuse is 19 pounds 7oz. which means the final dry weight is about 25.7 pounds. I can drop 4oz with a carbon wing tube and maybe 1/2 a pound if I do something with the landing gear. For now though I'm really happy with that weight.

[gareth.ky]

This thing has more blue glowy bits than my computer!

[TrojanMan]

Nice job Gareth!
I knew you could get it done!
Now for some test flights before the Tulsa Heatwave?!

[gareth.ky]

Yup its time to run some gallons through this thing.

You going flying this weekend?

[TrojanMan]

Yep! Let me know where and I'll be there.

[gareth.ky]

Wind for Saturday is supposed to be ~16 mph all day.

Too bad I don't have time to fly tonight. It's going to fall under 10!

I'' be flying it either at Guthrie or West Side. Guthrie is less crowded and has less stuff in the way of a dead stick.

[gareth.ky]

Wayne helped me discover a fatal flaw in my tail wheel setup:

YouTube - Tail Wheel Spring Geometry Issue

Going to try a whole different setup tonight.

[gareth.ky]

If anyone knows of some place, any place, that sells really tiny pulleys let me know. Like something you would see on a model sailboat.

[SunDevilPilot1]

Here is what I did.....

It may help you if you have some extra holes in your rudder servo arm about the same spacing as the tailwheel tiller.

On mine the innermost cables on the servo are going directly to the tailwheel. The outermost, on the offset bellcrank are going to the rudder. Both run through the same tubing.

In your case you could just hook the servo arm to the tailwheel tiller while utilizing the springs as a "servo saver".

Just a thought,

SunDevilPilot

[gareth.ky]

Oh snap, that's a really good idea. Thanks SunDevilPilot1!

I like how that gets around the issue of using some of the servo torque in flight to fight the springs. You can even use wider holes on the servo arm and narrower holes on the tail wheel to get some oversteer. With my rudder servo mounted in in the bottom it will be easy.

[SunDevilPilot1]

You may wrap the cables in fuel tubing where it will hit your carbon tailwheel bracket. Save on wear and tear.

SunDevilPilot

[gareth.ky]

I hate flight 0. You always know something is going to go wrong but you cant tell what. Sometimes its minor and sometimes its major. I don't think i have ever had a totally trouble free maiden. So today it was time to go out and get it over with.

The Good:

We ran the engine with the cowl off. With the factory needle settings it sounded pretty good. Loud, powerful and it idles like a swiss watch! I mean I have never heard a gas engine idle quite as smoothly as that.

I got everything buttoned up and did one last control check and cranked it up to maybe 1/2 throttle and it took off. It was immediately clear that it needed a bunch of down trim. Once that was under control it flew very smoothly. I'm not sure if the trim was a CG issue or just me not getting center on the elevators right. I'll investigate more tonight.

So I brought it around the first lap and the motor was kind of surging and I gave it a bit more gas. I don't think I got past 1/2 throttle the entire flight. There is no throttle curve so I know there's more stick left, as it were. It's flying very smoothly at this point and all is well. Just tooling around.

The Bad:

So about 1/2 way through the second lap we some some small yellow object depart the airplane WAY out from the field and I know instantly that its a wheel pant. I've become one of those pilots that can't keep their pants on. The hurtful part about this is, I have 4 longer bolts and nylon lock nuts at the field for the pants but I though I wouldn't need it. Think Again.

So I decide to land in case the other one is about to let go and sure enough it is starting to fall off. The airplane set right up to land and touched down without a problem. I was thinking I would have to go around but its really easy to land.

The Ugly:

On closer inspection the nut holding in the axle for the right wheel is missing and its just the wheel pant holding things together. I very nearly lost the wheel!

The wheel pants are my bad, I should have use the hardware I bought for them. We search the countryside for 1/2 an hour in the 100 degree heat but couldn't find it.

The deal with the axle is just stupid. It's a PSP Titanium axle. Its course threaded which that may have to do because of the metal. Its comes with some nuts that are no nylon lock nuts. Standard hardware store nylon lock nuts are too long for the nylon part to grab. I humbly request that PSP ship a titanium nylon locknut with their axles. I really like the C-clips they use instead of wheel collars. for now I'm going to switch to the Dubro axle. They come with fine threads and nylon lock nuts and I can cut them for the C-clips.

Special Mention:
Jersey Modeler. I think Dan was making fun of the big nipple that is the fuel dot. Those fittings really do work. All the way home I couldn't smell a drop of gas in the car. That, to me, is totally worth it.