wildnloose

I'm looking for some of these, care to share where you purchased them??

iron eagel

One of those should work fairly well. I tried using an Align heli motor in a plane and found that it worked fairly well but do to the high KV (3500) the bigest prop that it would handle was a 6X4.] on three cells.

iron eagel

One of those should work fairly well. I tried using an Align heli motor in a plane and found that it worked fairly well but do to the high KV (3500) the biggest prop that it would handle was a 6X4 (on three cells).

MJD

My Feedback: (1)

No prob - locally from Altecare - scoot down this page and you will see them: http://www.altecare.com/retairsysaccess.htm

I have a Savex L-39 jet, and it came with these. I don't know who the mfg is yet.

wildnloose

Thanks

airraptor

My Feedback: (66)

I dont think you will anywhere near 200 mph with a 28mm motor. You need to look at what it takes a gas plane to get it to 200 then find an electric motor that turns the same size prop for the same or less weight as the glow set up. a good motor choice and what I will be using on a QM plane is a Castle/Neu 1525 1.5Y CAR motor and a 200 amp speed control with a APC carbon 7.4x7.8 prop. I can spin that prop at 34,000 at 183 amps on a 6S pack

iron eagel

I don't recall all of the numbers exactly, but the Castle Creations flight calculator along with hp/thrust calculator both came up with, A prop pitch speed of 256 mph at 100 amps on a four cell using an APC 5.25X6.25 prop on the motor I am using. Now keep in mind that I know full well that I am pushing a heck of a lot more power through the motor than it 780 watt rating. If my plane is clean enough that the prop can get out of it's stalled condition, and the cooling system work well enough to keep the motor from frying during a three minute flight time I can get out of the pack, there is an outside chance that the plane may be able to make it to the 200 mph mark. At seed my AOA should be something like .0017 degrees to maintain level flight at that speed and my Demon has about the most minimal frontal area of any that have flown thus far. The motor I am using isn't my first choice by any means (a neu would have been nice) but the build was done only using what I had on hand without spending anything to do it. Besides it was all about keeping the weight at an absolute minimum it will have an AUW of 3 lbs flying on 512 square inches of wing and I am hoping that will keep the power requirements lower to get a bit of speed out of it.

airraptor

My Feedback: (66)

Good luck but I still dont think you will reach that speed with that plane. you are looking at around 2 HP or less with that motor put in to a 5" prop. the amount of thrust that combo will produce at 200 MPH is way less than the drag of that airframe at 200 MPH. I am not trying to burst your bubble or be a hater but I just dont see it. how fast is one of these with a Jett 56. These I think are around 2.5 hp at 19,000 rpm.

pitch speed doesnt really mean much. its thrust that pulls the plane forward. you need more thrust than drag. a 5 or even 6" prop at that power lever isnt going to do that.

also how do you know that 6" pitch prop is stalled? just because its over square?

Like I said you will need a 7" or larger prop to get over 200 mph. Now i would like to be proven wrong. I think you will need to fully sheet that plane and super sharp trailing edges. open bay covered with film will do what waves do on a lake at speed. They will start to ripple and slow you down.

At the power you are running that you are running the wrong prop. get a APC 6x4 Glow prop. its thin and very stiff for its size. yeah I know you will run that through your prop calc for pitch speed but dont even do it. run this prop up to around 40,000 or so rpm and it will make around 4.5-4.75 pounds of thrust on the ground and i think will be faster than that little 5.25x6.25. this prop does depitch some above 37,000 if you can spin it that fast

iron eagel

One of these airframes has achieved over 200 mph using a Nelson ,40 FAI engine that was piped producing around 3500 watts, it's AUW was way over 3 lbs with a fairly large frontal area. The frontal area of my airframe is only about half of that one so I am hoping that will play into into it's performance a bit.
Now how can I tell a prop is stalled, when the speed the airplane is able to obtain isn't around 85% of the pitch speed that should have been achieved at the rpm that the motor is spinning the prop at is a pretty good indicator, that along with the noise that it is making. The example I am citing is my Stingray using a 28 mm motor with a 6X5.5 prop on a three cell on it maiden flight was able to get up to around 160-170 mph turning around 26k rpm drawing a bit over 900 watts, with a 5X5.5 it was spinning around 28K rpm drawing about 600 watts but was only able to obtain 120 mph at best, but it sounded like a Pico spinning up like crazy.
Now as far as the airframe...
Both of my "speed planes" are fully sheathed so I don't have to worry about the skin distorting at speed and the trailing edges are honed carbon fiber, giving me trailing edges that resemble knife edges so they are pretty sharp, plus the Stingray has swept trailing edges as well. Funny you should mention the 6X4 that's what I intend to try on the stingray with the four cell instead of the three cell and the 5 inch diameter props.
My Demon is pictured below before the carbon fiber trailing edges were installed on the elevons.


At this point I am just experimenting with using electric power for a speed plane, primarily because I don't have the budget to get a really good glow power setup for what I would like to do, and I don't have the skills needed to trick out a glow engine to perform at the high rpms needed that I can get from an electric motor that is just off the shelf and can do it. It's been over 40 years since I have played with high speed airframes, and only got back into it after many conversations with Mike Connor about his designs. As a matter of fact my Stingray is based on Mikes PQ which had a flutter issue that would tear the airframe apart at about 130 mph, the construction methods I used seems to have eliminated that problem. Now I am just chasing the VNE of the airframe, my problem has been trying to get the right prop to get the best performance out of it, that along with the logistist involved getting everything to the field needed to launch the thing and the time to do it.

combatpigg

My Feedback: (3)

I run a 7x7 P7 Eliminator prop that I trim and thin blade past 2/rds
span
It ends up with 6 3/4" diameter
I give the props "Scimitar" tips....they look cool.
15 to 20 minutes to prep 1 prop for action
With the big cowl eliminated, you might be able to go down to 6 inches in diameter, but I'd start with a 6.5x ??atever your power is capable of handling to reach 200 mph on paper.

MJD

My Feedback: (1)

My stock Demon with some kind of fairing over the electric motor will be spinning a 6x5.5 somewhere around 1000W output on 5s and 1320W on 6s, 2500mAh. 6.5x6.5 on 5S is also a good option I will try out. I'd hope it at least reaches 150, if so I am happy (with this one anyways). I can't fit more battery than that the way the battery compartment is set up.

combatpigg

My Feedback: (3)

Without oily covering to deal with, making changes to these electric setups ought to be as easy as giving someone a crew cut.
My first electric speed delta would probably look like sin with "down and dirty" alterations until I settled on a system that did what I wanted without burning the plane up.
What I hate to read about are the melt downs. 20 plus years ago the first real hot electric flyer I met charged his packs in ice water.

iron eagel

I am going to have too see if I can fit it with a 6 inch prop. I am using a Ammo 28-56 3200Kv motor in this plane if it holds together it should prove to be interesting with even a four cell. For whatever reason CC flight Calc doesn't seem to like this setup it is giving me some weird numbers. I would anticipate that about a 2 volt drop in voltage due to the load it would be spinning up in the 34-35,000 rpm range drawing about 1400 watts or so. If I don't melt copper it should prove to be rather entertaining even on a 4 inch pitch.
Cp your right changing the motor is no big deal, yank out the battery and ESC slide the motor out after taking off the prop adapter and mounting screws.

MJD

My Feedback: (1)

I think the 26" Demon with a strong 28mm motor and a pair of 2S 2200's side by side for low profile would be a rocketship.

combatpigg

My Feedback: (3)

If I had a set up that could do 200 on paper, but with only a 5 inch prop, I'd build a small enough plane that could suit it and hand launch it out the back of a truck going about 20 mph. The truck really wouldn't need to go that fast, but dead into the wind. I wouldn't speed a lot of time on the first attempt to prove out the concept, just a film covered kite frame. If the first model looked promising, then build a cleaner version. I've had a 5x5 prop on a 20 inch delta do about 130 with a .12 size engine that ran 24,000 on the ground IIRC. Standing launches were dicey with me just giving it a level push at chest height. It used 2 HS65s [no fuel shutoff] and all other "1/2" sized gear, no muffler, no carb..so it was light as I could make it without going overboard.
I think the finished weight was right at 20 ozs

iron eagel

How about 27,700 rpm with a 4 oz motor and 8-oz of battery spinning that 5X5.5 with that 20 inch?
Bungee or Speedy's catapult for launch.
My 43 inch span Stingray flew fairly being pulled around with 5 or 5.25 inch prop just too much drag with that much wing to get the prop out of stall with that diameter, was doing around 120 with the 5X5.5 apc (sounded cool too just like a Pico full tilt). I bet the rpm would even peak higher once the prop started to unload.

iron eagel

Guaranteed!

combatpigg

My Feedback: (3)

I think it would need help at launch and the high wing loading brings the workable CG range down to a very slim margin. The engine I referred to probably weighed 4 ozs or less and it used a latex bladder tank that is practically nothing but the weight of 1.5 ozs of fuel.
If you can give a tiny plane like this a slightly low CG [high wing placement, or low slung cargo compartment] then it will be easier to handle.

iron eagel

Oh yea the one in the little red delta, those are real nice engines, but I could never get one running like you can it takes a real touch.
Yea launch assist is pretty much a given if your propped for speed.
With the electrics getting the COG right takes a fair amount of planning, even on the demon dealing with that 1 lb brick is a pain. With a shorter wheel base one like we were talking about, I think MJD has the right idea, split the packs would be the way to go. You just have watch out for the lead length big copper get heavy fast, not to mention the voltage drop due to the wire resistance dealing with low impedance loads.

MJD

My Feedback: (1)

ironeagel, given your digging into electric motor options for Demon deltas - I've been poking around ideas for sensibly priced and readily available motor packages. i.e not ordering overseas, and note we can't order from HK USA in Canada.

I thought this looked like a good package with a few % more oomph than a West .50/.52 system.. it is about as much weight as I think I want to use in the drive package. I figured on using APC sport props, the 8" are okay at these rpms.

p.s. figuring on two 3S packs side by side.

iron eagel

That looks like a good solid 175mph package for a full size Demon at a fairly good price. That motor looks to be a 35 mm diameter one, they don't list the width of it, is that about right?

Now if price were not as much of a worry, and you were looking for much higher top end, a Neu 1500 series and a 200 amp controller would shoe horn into about the same place. Either way after trying to accommodate a 4500 Mah 4 cell in my plane the split pack idea make a lot more sense. I can fit two 3300 Mah 3 Cells in that same space, which may be an option if I want to try a flight on 6 cells. As it sits at this point my plane could acomodate anything from a 4C 4500 a 5 cell 4000mah or a pair of 3300 3 cells so my options for batteries are fairly open. There is also one more 28 mm motor I could try a Typhoon EDF 1W-40 which is rated for 2400 watts 140amps as far as a cheap motor that will fit the current airframe without any modifications.

MJD

My Feedback: (1)

It's a 40mm stator dia outrunner. A bit large on OD but should be able to fair it in to a 1.75" spinner which is okay on the 8" sport props. I was trying to identify a motor package that doesn't rely on 35k rpm electric props and that would give a reasonable run time on 2500-3300 cells.

iron eagel

Interesting,

MJD

My Feedback: (1)

The BL32 2150kV motor I had in mind for the Demon is now screwed to the front of an E-flite Shoestring. I ran it up just now in the shop. Mu ears are ringing. 76A static on Graupner 6x5.5 "Speed" prop, 1440W input on freshly charged 5S pack. Static thrust ain't too much with the prop thrashing air like that, but once it gets moving it should be fine. I'm worried about the wing joiner. I stripped the stab and put CF uni on the structure to brace it up. Seems okay now.

invertmast

My Feedback: (23)

Here's my X-plane. Powered by a Kontronik Mini Pyro 400-14 (heli motor), YEP150A esc, 6s lipo and turning a 7x10 custom carbon folder. I believe the wattage should be around 3kw and good for somewhere in the neighborhood of 200+ mph