Posted by boingk |
Apr 23, 2011 @ 12:40 AM | 7,396 Views
With the HK GeeBee complete and awaiting pushrod material, I thought it'd be a good time to start another model. I've been interested in IC engines for a while and after ordering a Cox .049 and an AP .061 I started to build a wing from scratch.
Plans are here and materials used were 6 & 3mm square sticks, trailing edge section balsa stick and 3mm balsa sheet for the ribs. The fins are 1.5mm balsa layered up to 3mm, with an third part-layer on the outside. I left out the shear inserts because I didn't think they were neccessary. Heres the progress:
Made a few posts about this a couple weeks ago in the 3D and Sport Planes forums, and the other day the package showed up. Its a new offering from HobbyKing and their first true balsa kit. I got stuck in and heres where I am now:
The HK 3D GeeBee is dead easy to put together and takes me back to when I was a kid, making an Osprey (sic?) from a balsa kit and finishing with a tissue/dope covering. Only needed a sharp knife to trim pieces from the sheets, CA to adhere them and covering film & an iron to finish. No problems with fit at all, although I'd recommend using a 9g servo in the wing instead of the 5g they recommend as it a) fits better and b) will be better able to withstand the aileron flight loadings. 5g are fine for the elevator and rudder.
I've still got to fit all the electronics properly but linkages etc are ready to install after plugging some horns into the control surfaces. The recommended C20 motor fits well once you trim the fibreglass base at the inside edge of the mounting holes, and should deliver over 400g of thrust with an 8 inch prop on 2-cell drawing 10 amps... massive overkill seeing as it'll weigh 220g or so ready to fly.
The plan at the moment is to use this as a regular sport-plane and 3D trainer, as I have no experience with 3D flight except for some mild vertical and prop-hangers on my L4. I mean, I'm alright with loops, rolls (axial/barrel), stall-turns, inverted flight and other sporting maneuvers, but am yet to properly hover and so on. Hopefully I don't wreck the plane up too much learning, any advise would be much appreciated.
As the title might suggest, this installment primarily consists of my progress flying the FMS Mini P-40 and building of some balsa projects.
First up, here the P-40. Its all sorted out now and flies very well. I found the biggest difference to be the removal of the landing gear. It flies much better without them and bellies in fine for landings... provided you've got some grass cover. It cuts through the wind well, too, as you'll see in the video.
The balsa projects include the aforementioned Stevens Aero 'QuickOats 100' and my version of the StevensAero 'Adrenaline Rush', both reported to be fun planes to fly and not too challenging to build. The last balsa model I built was about 15 years ago as a kid, and these models are just fine for somone like me who is good with their hands but not too experienced in kit building.
Progress on the QuickOats is good, I've just got to finish the tail assembly and wait for my ordering of covering film to show up. It'll most likely be blue all over unless I order some more colours. I'd like a mix of clear, white and blue covering but I'll see what happens.
Progress on the Rush is alright, but I'm held up by the lack of motor mount... I ordered a while ago and its still not here. Whats gives, HK? Whatever, its not a big deal, just means I can't get it airworthy for a while yet. Heres the progress:
The equipment there is what I'll be running it with and consists of:
Its been a good couple of days for flying, and now the weather is closing in. Winter is on its way. No matter, last night I roared up the fire and started on the balsa QuickOats 100 from Stevens Aero which was kindly sent by dhdrover. Thanks again mate, much appreciated.
So far the empennage and left wing are together, still waiting on assembling the fuselage and right wing half. The internals are going to be from my Parkzone UltraMicro P-51, which was my first plane. It took an absolute battering and ended up requiring a manual hold of about 30% left aileron and down elevator to fly. Trim was useless as it'd give unpredictable deathspirals at useful levels. Anyway, its organs are going to a better home so it'll live on (ironically, in something that probably would've made a much better first plane).
The L-4 has been fitted with a Hextronik 24g 1500kv motor, replacing the 3000kv version of the same motor that was in there. I'm still running on 3-cell and have fitted a GWS 8x4 direct-drive prop. It works very well, giving huge thrust and moderate airspeed. Hovering is easily possible, as is 0~5mph groundspeed into a wind. I'd estimate the thrust/weight ratio at 1.5:1, which is about double what it was with the 3000kv motor. Efficiency has soared as well - I'm now using around 70~80mAh per minute in flight, so can get 6 minute flight times from my Rhino 3s 610's and 10 minute flights from the Zippy 3s 1000's. Both times factor in only using 80% lipo capacity, too. Nice.
The speed stick I'm working on hasn't seen any more... er... work but I am waiting on some major components like the motor mount and GWS 5x3 props. I'm planning to run the Hextronik 3000kv from my L-4 in it, with Rhino 3s 610's and an 8/10A ESC. Light and (hopefully) fast setup, should be fun.