Tests with 1800mAh 3S Zippy Compact. My Fuselage was modified up front for such LiPo's when it was an EDF ...
The voltage sag is excessive and LiPo is being hammered ..... so either a higher C rated LiPo is needed or use a lower kv motor.
The motor is one of the pair I had fitted to my infamous Parkjet Twin ... the power draw then was over 110A and too much for the PKJ Twin set-up.
BUT - the set-up shows substantial thrust capability ... while holding the model - she was pushing VERY hard against my hold. She would be quick I'm sure.
Trouble is the motor mount then had problem ... the rivets holding the L plate to the bracket worked loose with the thrust. The mount will need replacing, but I set the beam so that I could do this if necessary.
Balance ? Perfect with the 1800 3S and servos in original positions ... ESC pushed into the upper area immediately behind canopy.
I'm really looking fwd to fitting a new mount and getting her in the air ...
I was thinking about doing the very same thing on my tired Red Arrows T-45. Have a Grayson Super Mega V2 (2550) that I could use. Where did you find the bolt-on sandwich bracket for the stick motor mount ? Looks like it stands-off around 30-40mm out the back? 6x4 e prop?
The mount is the HXT Alloy Metal mount from Hobby King ... go to Electric Motors ... Motor Mounts ..... halfway down first page.
BUT note that the mount is brittle ... I broke one on a Parkjet before. The one in photos above was made by local metals guy - but proves to be not so good ... he riveted the L to the original HXT bracket.
I'm hoping that being in the duct - will protect the alloy mount ... I've just ordered 2 more. Plus a Rare-Bear motor to fit with 4S instead of the 3700kv motor ... bringing amps draw down.
I might just experiment with mounting the the motor on ply directly to the aft with hot glue. Outrunner versus inrunner like my profile foamies. Have a 50 amp esc available for 4S. Then try to balance with lipo in the cavernous cabin. I'll at least give it a look.
I did it but will it fly? Heck, given enough power,a brick will fly, right ?- LOL
Mounted a Grayson Super Mega V2 off the hind end. The x mount is screwed into hardwood then to a slightly larger piece that covers the thrust hole. This piece is hot glued. Seems pretty solid. Of course, she's grossly tail heavy as expected. But since the forward cabin is so large, I was able to load a 2200 3S 25C lipo in there. Actually balances pretty good but the AUW has got to be at least 2X what the edf version is. My scale is broken ut just handling it , I can tell. Will go with a MAS 6x4e and see what happens.
Probably should drill a couple cheater holes so the air can flow through.
Only reservation I have with the plate ply mount is the blocking of the duct. The inlets on the model are large and I reckon if air cannot flow freely will present a brick-wall to forward flight. With the beam mount as I did - the duct is literally as clear as with an EDF ... so air should be able to feed the prop as well as cooling the motor.
I considered using an X of ply across back end - but then would mean I cannot change / service motor easily. This metal mount although brittle - allows me to remove mount and motor in one piece and access is good.
I too can balance with a 2200 3S or a 1600 4S up front ... but I'm going to hold back on the 4S test till I get new motor and mount in place. I'm very worried about the present mount. It is loose on those rivets and being alloy - would not take much to pull free. I have considered breaking the rivets and replacing with countersunk self-tappers into the wood as well. Might just try that today. If it works - then she's a go'er !
I do share the the air flow concern you mentioned in blocking the exit tube. Going to drill some holes on the sides of the intakes to direct flow in line over the tail. There is a small hole for the wires at the back end. I 'll try it and see what happens. Man, this baby is heavy with the 2200 mah lipo in there. Balance seems pretty good.I recon she weighs about 17-18 oz.
I swapped out the 4.5 x 4.5 prop to a 4.1 x 4.1 .... made big difference to amps draw ... and SCREAM !!
The volts were much better at WOT .. showing 10.4v on the 3S and 34A ... 12.3v and 56A on the 4S (that's not so good).
The prop was still pushing hard and will definitely have her going reasonably. I honestly think the duct being clear allows the prop to draw air and once flying - I expect the duct to assist even more by directing the air direct into it ...
Looking forward to hearing about your test results. Will try to give mine a go tomorrow if the weather holds up. An interesting adventure to say the least but it took me all of an hour to re-configure and setup and 0$. The T-45 is my favorite of my small Skyangel squadron. Hopefully, she'll see some more time in the air as a pusher.
Made it to the field this afternoon around 16:30. 70F deg temp.
My buddy, a French MD-80 pilot and his son were there flying their new FMS 1700mm Corsair. Gorgeous plane. Started off with my newly re-furbished Airfield/FMS C-182. All good. Then, the Dynam C-310, a real gem. Now it was time for the test of the T-45 pusher. Video included below
-Grayson Super Mega V2 w/ 40 amp esc
-11.1 2200mah 3S 25C lipo
Wow ! Was a blast but scary. Underhand toss. Managed to loop her over and back through the hangar. Didn't touch a thing and I don't know how. Over the road and then back over the field again. Yikes ! Took everything I could do to keep her from augering.
Now I know what adjustments need to be made. I need some ballast in the front though I thought she had balance ok. Wrong. Going to drop a couple of AA batteries in the nose. With the power she now has, I'not concerned aout a little extra weight. I can say she does indeed have plenty of power to spare. Crazy power. Recon she's a lot faster than the edf version.
Ha Ha Ha ...... I know the feeling well !! My first success with my overpowered Parkjet was similar ......
The funny thing is - the thing to do just escapes you - Close the throttle !! You are so intent on getting the thing under control - like me - you forget there's a throttle.
OK - I have a theory that pushers require more downthrust than a tractor ... the fuselage inertia means pusher tail is trying to overtake the nose ... so needs downthrust to force model to fly the wing instead of the thrust.
Watching yours makes me look at adding another washer in the mount !!
So at least we know there's potential there for some hot stuff ! The EDF version with me has hit a wall at 140kph ... so maybe this will break that, get her faster.
Well done on managing to save her !!
Keep updating so we can all benefit and have a laugh watching the vids !!
Must be nice to have good tools and a good work area. All my good stuff has been in storage for over a year. Need to get it out. Been working with primitive make shift tools and have confined to my office when the wife is at home. One time, I spilled a tiny drop of epoxy on the kitchen table and that was it !
Fuse re-config looking great.
It's Springtime in Texas but that ususally means wind. March is our windiest month. So when it dies , I head to field on a moment's notice. Might give the T-45 another go today if the weather holds. Will try not to fly through the hangar this time. I know if our President would have seen that I'd probably be facing a suspension. Yikes !
Good idea on the down thrust. I should have known this from my earlier profile foamie PJ's. Maybe 2-3 degrees with a shim. Looks nice out there so far today so I may try the front ballast making her slightly nose heavy and re-test. Of course, far away from the hangar ! Underhand toss worked good. Arm clears in time to avoid prop contact.
I'll post another vid later but I did get out there today for a re-test. Loaded 2 AA batteries in the nose for ballast. Presto ! it worked. This baby has new life ! Trimmed her out and she wasn't wonky at all. Flew great. And I must say, very fast ! But late in the flight, in a dumb thumbs moment, I crashed her. Landed flat on her belly but there was virtually no damage. Not even a broken prop.
Threw her up for another go and proceeded to torque roll her into the ground. Must have been a twist of my wrist on the underhand toss. Motor dislodged, broken prop but no airframe damage whatsoever. That's okay. I now can go ahead and include a couple degrees of down thrust when I re-mount the motor.
There's life in the old gal ! Sure outflew my 50mm F-16. I'm pumped. Thinking I'm might even get a new T-45 airframe and do it right but it wouldn't be the same as re-birth . Vid later.
4S 1600 35C Zippy Compact (tired used !)
AUW : 618gr
Thrust initial : 1030gr
Thrust after 30secs : 960gr
WOW @#$%^& WOW !
Only problem with the 4S - is she is really pulling amps and the ESC would give out if pushed too long ... it's a HobbyWing Pro 45A ... needs a 60A on the 4S ... but on 3S she's fine. I could fly the 4S ... IF I can keep myself from WOT all the time !!
My question now - is downthrust too much given that this thing will mooooove !!
Dahawk ... what is the KV of the motor you are using ? Once you get her dialled in - can you get some straight level passes for the ol'doppler ?
I think you need a better camera !! Why not do as I do for most - a Keychain camera with Velcro onto a baseball cap peak ? About $5 for the camera ... no need for HD ....
Weather is crap for next days .... but looking fwd to this baby in the air ... I'm hoping that my set-up will do the 150kph and beat my EDF version ... maybe even higher ... theoretically I should get about 180kph ... but I suspect the airframe will hold her back.
Anxious to see your results Nigel ! Yeah, Underhand worked best for me. Was a little concerned about prop bites and my hand seems to clear faster this way plus I can get a better hold on the fuse. Will look into a better camera set-up. I have an HK mini keychain cam but never tried it.
After this one, I think I may go ahead and convert the Katana. I have not had great success with this plane yet. Even with the Don's 4800 4S setup. I think it would fly better as a pusher given the proper amount of power. Now I have to go back and re-install the ailrons on the F-16. What a mistake it was to go with elevons only on that plane. Zero roll rate.
Big T-storms rolling in here ! Everything big in Texas. Fix up time !
P.S. Just bought a GWS Formosa II F3A pattern ship ARF - USD $50.00 Figured, what the heck, could not resist since I have everything I need from my T-28(RIP) !
P.P.S.- The plane I really have a hankering for is the 1200mm HK Top RC Focke-Wulf 190 Butcher Bird. What a beaute !
Keycam's nifty little machines ... I have a couple ...
Don't let battery go dead !! Simple Velcro on the cap peak is good enough .. only thing to remember is field of view is not as much as your eyes .. so when doing runs from one side to another - you tend to lead the model with your eyes - putting it to the edge of camera view ... takes mind over matter to make you keep head toward model and eyes leading !!
I keep looking at the F16 in 50mm ... one of the few US fighters I like ... given the problems of sorting it to high power set-up in EDF ... maybe pusher is way to go with it ? I'm surprised that an F15 50mm hasn't been made ... that would be a good one I reckon.
The Depron F15 I made is really good and proves the aileron / tail link-up in small model ... the pitch control is excellent and roll rate is WOW !
I'm not surprised about your F16 ... the plane has a lifting body config - so you are not only fighting the wing / tail surfaces - but also a large fuselage area ...
Katana in my eyes is a mini 'Stinger' ..... and judging by reports not as fast or capable as it's 64mm cousin. For a few $ more - the Stinger may be a better bet ?
Screamer is not on my list I'm afraid ... too many delta type wings already out there ... so a hard market to enter.
The 190D ............. one of my all-time favs in WW2 birds. I had a Rojair 190D with Enya 35 Glow up front years ago ... loved it. I keep looking at plans for an electric version ...
HK does a parkflyer sized one - Pirate FW190 ... but Latvian post limits refuse it......
I'm due to travel out again shortly - so hoping I can get the T45P as I now call it ... T45 P for Pusher ...... airborne before I go ... I also have the Pkj twin to fly.