I nearly bought a Hydrofoam about 6 or 7 years ago when they first came out. In hindsight it was probably a wise move not too as it would have ended in tears and a bag full of foam.
After seeing B-Money's RC Powers hydro 150 my interest was sparked once again, the extra size and the dual motors with the counter rotating props to eliminate torque roll, I was sold.
However I wasn't too fussed on the boxy look of the spontoons and the tall single fin of the RC Powers design.
So I've taken the free plans from Parkjets.com done up by Prop-er and scaled them up to 167% so that they take up a whole 1000x700 sheet of Depron.
I went with these plans for a few reasons,
1. The fact that the scaled up size gives approx 44cm betweens the spontoons which should allow me to fit 2 6x4 props and a cockpit of sorts.
2. The width to length ratio is higher which should be more stable.
3. The length of the spontoons is slightly shorter which will get the motors further forward which should help me get the cg right, I hope.
4. These plans have a lot more keyed notches which I hope will add to the strength of the joints.
I just watched a video on one of these, looked pretty cool cruising around a lake, i tell you what thought, i almost **** when it took off from the water and started flying, i did not expect that at all. Freaken cool.
There is a lot more cutting to do on this than the f117!!
I have finally gotten the bulk of the pieces cut and it is starting to come together
Got too keen to get gluing and forgot to add the carbon before gluing one of the side pod pieces
Forming up spontoons, lots of trimming and shaping to get it all to come together nicely.
Starting to take shape
One spontoon nearly finished, glue went off too fast, had to scramble to get it together.
I still need to source some ply for motor mounts but havn't yet found what I need. Motors, props, esc, servos & batts have all arrived.
Did some tests on the 6x4 3 blade prop on the 2826 2200kv. Got approx 800g of thrust @ 27amps on 3s, this should give me over 1.5kg of thrust. I hope to pull this build in under 1000g.
The arrival of some much needed hardware has sparked life into this build.
Control surfaces hinged & control horns fitted, servos fitted, control rods fitted, motors fitted.
Fired up the motors last night for the first time, they are really loud, they must resonate through the foam and gives out a really loud high pitched squeal. Would hover at about 2/3 to 3/4 throttle.
Have dialed the roll back to 50%, pitch to 75% and set 50% expos all round to calm things down.
She's 1100mm long, 700mm wide and stands 280mm high, I've still got to epoxy coat the skidding surfaces but at the moment she's weighs 966grams.
Hope to at least give her a ground run this weekend if not maiden her.
Ok, gave this a "maiden" this morning, one thing is very clear, it is way tail heavy. Made for some very interesting "flights" trying to keep it level.
Had a few rough landings and nearly parked it in some trees but she has come away in mostly one piece. Have cracked one of the sponsons on the top and most likely split the carbon reinforcement inside as well as one of the vertical stabs, also one of the elevon control rods came loose.
The rudder control is very anemic and it really didn't want to turn right at all.
Effected some repairs/changes overnight, glued the stab that had cracked and added another carbon spar to support the sponsons. But most importantly added 30g of lead to the very front of each sponson, so 60g on the nose has brought the cg forward by approx an inch making the cg approx 80mm back from the leading edge of the "wing".
Took her for another "fly" yesterday morning and it was much better to fly, only getting about 5min runtime with the 2 motors so still need a lot more stick time to get familiar with it and start to do more than just takeoffs and landings.
Thanks for your comments, will keep you updated on how I progress.
Had to cover the whole bottom of the front sponsons with araldite to prevent further wear to the foam, this has added another 60g or so, but up front so not too bad. This has meant that I've only got a single 14g mag wheel weight on the front of each sponson and it flies quite nicely. AUW is at thr moment 1070g, Runtime is pretty much 5min if your game to push to the end.
Tried to push my luck and fly in way too windy conditions, was getting blown away while on the ground! in the end I stalled it about 5ft off the deck resulting in a cartwheel "landing". Check out my other videos for those. A bit more gluing and she's ready to go again.
Is dipping the right hand side on lift off which is I think due to the glue of the repairs as it was dipping left prior to the cartwheel which damaged the right spontoon. Gonna try the camera up on the left spontoon tomorrow morn see if that changes it.
Is also pulling left on high Alfa, this requires full right aileron, d/r only @ 70% tho, and it still won't go right. I have upped the d/r & added a little shim under the motor to move the thrust line right a little. Will also see if this makes a difference in the morning.
The right thrust I added made a little bit of difference, I was able to at least stop the left turn tendancy in high alpha but this still required a lot of right aileron. I'll try putting a bit more in and see if that makes it any better.
That's really interesting to watch. I like how well it turns and powers on when it's on the ground. Could be a new type of land craft for racing, even without the abillity to fly. Thanks for that!
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