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Inq'd Turbo Storch

danskis

Master member
#61
Just curios, are there many scratch builders at the field? Not too many where I fly power - a few of the glider guys build kits.
 
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Inq

Well-known member
#62
Not that many here either. Most seem to have the foam silhouette or injection foam type kits - A-10, F-16, F-18. One guy just finished off a scratch built GeeBee. He did it from a one-page set of plans out of a magazine. He spent over 500 hours on it and its gorgeous. But, I've only seen a small fraction of the 50+ members. Some told me there's one guy that spends about $10K a year on this hobby... builds jets, uses a real turbojet (not EDF), crashes it and starts over. Haven't met him yet. I haven't seen any glider. A couple helicopters, about a dozen EDF's. Mostly 3D, Acrobatic type planes. I'm the only one that is doing FT, DTFB type OR 3D printing planes. I've gotten a lot of interested questions about both, but I haven't seen any takers yet. Although, I thought it interesting that the GeeBee guy sounded like he wanted to make the FT Stroch.
 

Tench745

Master member
#63
I was going off just the specs on that Amazon page, so I'll definitely check out your Altitude Hobbies reference. I'm making plenty of assumptions in its selection. The 432W it can put out, I'm sure has to be at the 4S. That's 28 amps and too close for comfort to my 30A ESC. But... I'm assuming using 3S batteries should reduce that current draw significantly especially if I'm using the same 10x4.5 propeller. I'll definitely bench test it to confirm. Even with 3S, it'll be more powerful than the 160 watts the 2212 puts out. Although the 28xx motor probably would have been a better choice for the Storch, I wanted something that I could transplant into say an FT Spitfire (that will have to get the Inq treatment too:sneaky:) and upgrade to 4S and get the full 432W. This is also good enough to go into the 3DLabPrint planes I have gathering dust.
This might have been discussed before, but I can't remember anymore. The way you talk about amps and power sounds like you're missing the relationship between motor size, prop size, amp draw, and wattage.

It takes a given amount of power (watts) to spin a propeller at a given RPM. If it takes 160 Watts of power to spin a 10x4.5 propeller at 11000 rpm it doesn't matter what motor is doing it. Both a 2212 motor and a 3536 will both need 160 Watts to spin that prop at that speed.

If you want more power you need a bigger prop (which draws more amps) or a higher RPM (more volts).
What a bigger motor gets you is the ability to pass more amperage through the windings which will let you spin that larger prop without torching the motor. (You also get more torque, but that's not relevant to the point I'm trying to make.)
 

Inq

Well-known member
#64
I've got a little background in the EE power/volts/current/resistance type calculations, robotics, micro-electronics and building a battery system for my sailboat. I think the point I was trying to make (but didn't elaborate)... the larger diameter and longer rotor should be able to tolerate more power AND will create more torque to allow it to spin up further. IOW, assuming they have the same efficiency (~70 to 80%) and are both using 3S batteries... at the same speed... Yes, they should be drawing about the same current. However the A2212, 1000KV is maxed out at 160 watts, delivering only 59% of its KV speed rating because of the prop drag. I would assume, the D3536, 1000KV will not be maxed out and exceed that 59% easily. Yes, it will be using more current at the same 3S voltage, but it will be delivering more RPM and thus thrust. At least that is the theory I'm going with until I get the motor Saturday and confirm or get disappointed. Right or wrong, I'll be reporting either result.
 

Tench745

Master member
#65
Yeah that's pretty much the gist of it. Now I feel silly for explaining.

Off topic: what sailboat? I sailed an O'Day 25 for a number of years and helped a friend rehab his Valiant 40.
 

Inq

Well-known member
#66
Yeah that's pretty much the gist of it. Now I feel silly for explaining.
Nah! Don't. I came off, half cocked, mixing metaphors and mixing wattage and amps. You were right to call me on the carpet.

Off topic: what sailboat? I sailed an O'Day 25 for a number of years and helped a friend rehab his Valiant 40.
Now, I'll be embarrassed to say in front of real-sailors. I learned on a Hobie Cat... but like getting married, and trading in the sports car for a station wagon, I got a MacGregor 26M. But... towing kids around on innertubes, even water skiing, sailing in protected bays and a little in open ocean, able to sleep four pretty comfortably... I got good usage out of it. I've always wanted to upgrade to a cruising cat... say 40'. I even burnt many an hour trying to design my own...

Did the fluid dynamics on the hulls, optimized to be competitive as a racer/cruiser. I had dreams (delusions of grandeur) of mixing it up with Gunboats.

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End the final analysis, it came down to not having a place to build it and now... being land-locked and with a wife that really doesn't handle ocean swell well, I think that's one for the next life. :rolleyes:
 

Piotrsko

Master member
#67
While that part of motor theory (physical size) is true, winding count, wire size and power timing are an important factor in converting watts to magnetic force and subsequent heat rejection. Not so sure about low voltage back emf being a factor.

Don't apologize for the hobie. As a Sabot driver, that would have been an upgrade for me.
 

Inq

Well-known member
#68
Don't apologize for the hobie.
:ROFLMAO: I'm not a bit ashamed by the Hobie. I picked it up for free... a tree limb had fallen and holed one of the hulls... it sank. The owner was glad not having to deal with disposing of it... "Just get it off my property and its yours." I fixed it up, self taught and got to the point, I could sail it onto the trailer and was flying hulls from the trapeze solo in the Atlantic... (when I was young and stupid). Finally pitch poled it bad enough to throw me onto the mast and crack a rib. The journey home confirmed, I'm not Superman after all. :cautious:

The station wagon (MacGregor) is a totally different manner. Always regretted getting rid of the hotrod.
 

Tench745

Master member
#69
I met a couple cruising the Erie Canal on a MacGregor 26M. It looked like a load of fun, fast, and quite spacious below.
I met a gentleman in the Chesapeake who built himself a 38? foot catamaran. I got a tour when he had it pulled up on the beach near where I was anchored. His daughters were having their friends over for a birthday slumber party aboard. All that space and a diesel heater sure looked nice in October.
 

Piotrsko

Master member
#70
A mac 28 had more room than a Cal 32. Lusted after one but couldn't afford live aboard berth anywhere in LA or Orange county. Btdt with the hotrod, but ended up with a normal vintage '66 4 door sedan. Wife isn't a wagon fan.
 

Inq

Well-known member
#71
The Turbo Storch flew yesterday. The last day ended with a burnt up motor. The motor was new, but the same cheap 2212, 1000KV kits. It could have been a bad motor or it could because it wasn't getting enough cooling with the spinner attached. Yesterday, I used another 2212, 1000KV motor, but without the spinner. It didn't seem to have any trouble. I probably did 15 take-offs and landing and only had two nose over. It is the first time I left the field with a still flyable plane. SCORE!

I reduced the aileron rates to 75% rate and 80% exponential and it is still way too touchy with the full length flaperons. Any time I tried the flaps it would allow it fly even slower, but it was even harder to control. I've decided to cut the break between the flaps and ailerons and fix the flaps. Hopefully this with reduce the touchiness of the T.S. The video does not show any flight time with the flaps down.

 

Inq

Well-known member
#72
RIP... Turbo Storch.

Although really easy to fix - the wing is fine, the body is fine, just a little firewall forward issue. I feel I've graduated (maybe hubris) from the trainer stage and actually needing something that penetrates the air a little better (see post in "What did you crash today" if interested).
I'm under the belief (as misguided as it might be) that it was not caused by the Inq'd mods. I'm on to Inq'ng something else up. At the moment, I'm thinking a Spitfire needs Inq'ng!

 

Inq

Well-known member
#73
Not that my last post gives you lots of encouragement... but it appears that the resources for the Inq'd Turbo Storch are now available. I'll back-edit the posts above so they can easily reference the Resources. If anyone cares to brave it, please let us know (me and any other unsuspecting) what you learned... what I can improve... especially when it comes to other materials (LW-PLA, PETG... etc). Thanks.
 

Tench745

Master member
#74
RIP... Turbo Storch.
Although really easy to fix - the wing is fine, the body is fine, just a little firewall forward issue. I feel I've graduated (maybe hubris) from the trainer stage and actually needing something that penetrates the air a little better (see post in "What did you crash today" if interested).
I'm under the belief (as misguided as it might be) that it was not caused by the Inq'd mods. I'm on to Inq'ng something else up. At the moment, I'm thinking a Spitfire needs Inq'ng!
Ooh, that looks exciting. Was the crunched nose before or after the toasty ESC?
 

Inq

Well-known member
#75
Ooh, that looks exciting. Was the crunched nose before or after the toasty ESC?
Snoopy went down behind the hill, but the motor mount does not show any signs of heat deformation... I deduce it was familiarity with the ground. :rolleyes::cry: I have not really studied the extent of the fire (and there were flames) on the receiver and wiring. The motor looks ok, the ESC is a smoldering hole in the ground and other wires in the bay are melted... some all the way through.

I hate repairing... I'd rather start from scratch. :cool: