gtmaxx

My Feedback: (6)

Has anyone here bought or flown the Ultrafly BAE Hawk pusher prop electric jet - like the one sold at Tower Hobbies? I ask because myself and a buddy bought one each. He just finished putting his together and made her as light as possible and even with Lithiums, to meet the target weight of 570grams or less will almost be impossible. He's an accomplished builder and has been building planes and helos for year so I know he's done the best that can be done for the best possible set up here. To get their required CG would require a lot of nose weight and thus would put us over the weight limit which Ultrafly highly stresses against doing. How the h#ll can they be flying that plane on their website video using NiCad or NiMH batteries is way beyond me because the weight for 12volt setup for performance (per their recommendation) would be even higher yet. Can anyone here or elsewhere shed some light on this?? It's a nice looking bird, but **** - not worth anything if your going to fly a rock. Don't mind high wing loading as we've been their and that many a time - but this will be putting us over their highly stressed weight limits. Just don't want to see others buying it only to find out that they have a $90.00 nice looking paperweight + all the other $$$ spent to get this airborne and have nothing but nightmares with it. Really could use any and all input on this one guys!!! You may also e-mail me directly at: [email protected]


Thanks,

Todd Walters
GT-MAXX Inc.

skyhawknut

My Feedback: (3)

It flies very well on the stock setup. Even with nimh.

See for yourself............ http://www.rcgroups.com/forums/showthread.php?t=254983

tonycorn

Hello Todd/GTMaxx,

Just finished a 'Hawk' with the Ultrafly brushless set-up, Kokam 3S lipos, 80% of the decals, Dubro pinned hinges instead of the weird ones included with the kit and used Zap 5-min epoxy (sparingly) on virtually everything. Weight came in at a shade over 500g. In fact, had to add weight near the nose to get the damn 'CG' correct. Used 2 x 7g stick-on Great Planes lead weights for that. Maiden flight will be this weekend, weather permitting. I've done a few 'system tests' and at full throttle, it wants to jump out of my hand. Receiver is a 6CH micro JR that I use on 'PPM' mode with my Futaba 9CHP.

Expectations are high for a successful flight. Am about to start (anaother) GWS A-10 with EDF-55's and brushless motors. My first A-10, which is still OK, was well over-weight as I just slapped epoxy everywhere and didn't pay any attention to 'weight control'. DOH! If A-10 #2 works OK, #1 will end up being a nice mobile hanging over my son's bed!

Best of luck.
TC in Sydney

davbow

My Feedback: (6)

Beware of the "dreadful roll" on takeoff..... With the torque the engine puts out and minimal airflow over the wings during launch, she tends to want to roll

2605

i just finished my ultra fly bae hawk 580grams is the weigt whit 3cell lipo 2000mah
i will have the maiden flight tomorrow i hope

2605

i just finish my ultra fly bae hawk 580grams with 3 cell lipo 2000mah[8D]

2605

have anyone been flying with their bae hawk

iflyrotors

I flew mine a couple weeks ago, it flies great, just a little scary landing in a small field . I've got a Thunder Power 3 cell 2100mah lithium powering mine, with a castle creations pixie 20 speed control. I broke the nose a couple times because the prop was on backwards (yes, I know i'm an idiot : ), but after some glue and carbon fiber all is well. Haven't weighed it though, so i can't say if i'm heavy.
Chris

b17flyer

My Feedback: (32)

did any of you have a torque problem roting to the left on take off.? I 'm upping the ail throw to compinsate.

rmac714

Flew mine first time today. Launching is awkward. The finIger holes are'nt deep enough. I held the fuse just aft of the main wings. First launch with half throttle took a large chunk of finger with it. Ouch! Didn't stop the flight though. This is an amazingly fast little plane, perhaps a little too fast for such a small WS. I have a Himax 2025-4200, Cobri gearbox geared at 5 to 1 and a 9070 prop. 70mph fly-bys with literally unlimited vertical. Don't know how long it will go straight up, I would back off when it became too hard to see. Trimmed to fly straight at full throttle, when you cut the power the lack of torq is evident. There is such a small wing area, that it wants to roll. This can be compensated for and if scarey fast is your thing, this will do it. Had no small number of experienced flyers very impressed today. The biggest problem I see with this one is the landing. When you come in so hot with a plane so flat on the bottom, something has to give. Every landing caused the wing to come out of the fuse at the front. I don't see a patricularly long life for this one. I also intend on bungee launching this model from now on.

b17flyer

My Feedback: (32)

have had a 10+ flights now and its a good plane. I putin a carbon fiber strip to keep the plane from flexing it wings.
it actually lands slower than one might expect. I'm using the finger holes with no problem. quick throw on 1/2 power then go to full.
using 3cell 2100 lipo and the brushless motor that ultra fly sells for it.


CAN't wait for the su27

rmac714

I'm using the Thunderpower 2100's. I finished my landing gear tonight, complete with steerable nose gear. I'll test it out tomorrow. I put the mains right on the cg with the servo and gear in the nose, allowing me to lose the lead I used for balance. I added a total of 1 1/2 ounces with the gear. I have to really get the speed high and rotate up slowly so that the prop doesn't hit on take off. I just feel more comfortable taking off and landing on a set of wheels

spitgy

I'm considering one of these things - what prop is used for them? Do you use an electric type and just turn it around or what? If you've ben flying the hawk for awhile, where is the weak link?
Thanks guys

rmac714

I used a e-flight brushless 400,(4200kv), geared 4 to 1 Cobri gearbox, 3s 2100 thunderpower with a 9 x 7.5 prop. Absolutely ballistic flybys and almost unlimited vertical. Not for the timid. I have in fact retired mine after only a few flights. Almost took the end of my finger off on one launch. Too hard to get in the air. Even tried gear with limited success.

spitgy

rmac714 - thanks for the info. Did you fly it with the stock motor? If so how did it go? I was wondering if you could use the stock setup w/ a Lipo? Whats your opinion? Will the stock motor accept a speed controller from a brushless motor? As you can tell, I don't know that much about electrics so any input would be appreciated.
Did you try launching with power off and then hit the throttle once it was in the air - avoid finger bites this way.
Thanks again.

julianb

Hi there,

I've been flying my Hawk for a while now on the Ultrafly '24' brushless, not the '29' I get better duration with the slightly lesser motor on 10 GP 1100 NiMh cells.

If I was building another I would throw away the glass wing spar and replace with carbon, then glass the underside of the wing and fuselage with 0.5 oz cloth.

The roll on launch is an absolute *****, but I've found an under-arm toss works just as well and 9 times out of 10 the roll isn't evident. Running direct drive and a smaller prop would most certainly cure this trait- but the Ultrafly motor is an outrunner, so probably not best suited to turning high-revs.

I don't like the Ultrafly 25 amp speed controller - I was getting all sorts of radio interference which stopped when I replaced with a Jeti 18 Advance. It pulls a few more amps, but the increase in performance is visible!

thanks


Julian

T-minus-1

Julian, actually the ultrafly "24"is good for running direct drive with up to a 6x4 prop. you just need a 2.3ml prop adapter. the 29 is not recommended for direct drive though. I have been using the "24" direct drive on my Stryker with a 6x3 prop and lipos. i get 10 minute flight times with that setup and it could definately push the hawk. i have the hawk too but have not reall flown it yet, i wanted to get used to the brushless power in my stryker first, as it has already seen some battle damage.

Also i have the ultrafly 25 amp speed controller with no problems, i have found that if i am getting any interference it is most likely that my antenna is too close to a servo wire or a battery lead wire.

tusk91

I am using a direct drive on my new Ultra T-45, and I have the motor mount attached upside down for prop clearance. Not sure how that will work out yet as far as the thrust line is concerned. First flight as soon as the weather gets clear!

My Setup:

400 Outrunner Brushless Motor (10 amp draw)
GWS 7X8 Prop
Thunder Power 3 cell 2100mah
15mah ESC
Weight is just under 17 ounces

_____________________________

Brushless F-27 Stryker, Brushless Aerostar, Brushless Ultrafly Bae Hawk, Brushless EDF Kamdax Mig-15(on order)

T-minus-1

i wouldnt know if the line of thrust will be a major factor, but when you maiden that thing be sure to really throw it. your motor/prop may be giving you a lot more thrust than mine, but motocalc rates my setup at 15ounces static thrust and i have to throw mine really hard. i also have a brushless stryker and launching the hawk is nothing like it. the stryker is so much easier.

julianb

HI,

the Mega 16/15/4 is giving over 180 Watts. I can't launch it at more than 2/3 power or it just torque rolls into the floor!

I find a good crisp underarm 'flick' get's it away. I think I'll build a bungee launcher for the next one.

I can't help thinking it wouldn't be so bad if the model was a little larger. In comparison the SU27 is a real *****cat.


thanks


Julian

T-minus-1

after i get a few good flights on the hawk i think i want to get the su-27, so its a ****cat, huh? do you like it better than the hawk? it sure looks good in the pictures and videos.

clovus

Hmmm,

Any pointers on a succesful launch? I've got the Su-27 and so far have only had nasty crashes - I've tried running throws, no throttle/half throttle/WOT and it still rolls left. By the time I get my hands back to the sticks it's all over red rover.... and another session with the glue....

As I'm kinda fond of all the digits on my hands maybe a bungee is the answer.

Has anybody used a bungee...or any ideas how to set one up?

T-minus-1

clovus,

im curious if you have the brushless motor that you can get with the su-27? if you do it seems that thing should just shoot out of your hand like a rocket.

JulianB who has posted on this thread says try an underhand toss, but i personally have not tried that, i trim my hawk's ailerons to the right a lot and correct the trim in the air, and throw it leaning a little to the right, it still rolls left but doing those things allows me to take off.

also important, make sure your prop is not on backwards, which kills your motors power even if it does not feel like it when you hold the plane and throttle it. since its a pusher you have to reverse the prop, so the writing, or the size on APC props (like "6x5.5") faces towards the nose of your plane.

clovus

thanks for the advice T,

I double checked the prop before the first flight and could feel the wind pushing out from the back, and holding it to my workbench with WOT made it really want to creep forwards, even with me holding it down.. so I think it's not the prop.

Maybe the motor does lack a bit of power as I thought it would do unlimited vertical, so launch easily with a gentle toss. Perhaps it's due the extensions from the motor to the ESC. I needed to buy some 16 guage wire to connect the motor and ESC (approx 20cms in length).... I got the same thickness as the ESC, but the motor wire was very thin.

Perhaps my soldering is lousy.

I will try to put a bit of R aileron trim in to see if it helps....So far I'm a bit disappointed, not so much with the plane ... heck it looks great (well it DID look great, now it has no nose) .... but maybe with the way I built it.

Oh well, it's only money...

T-minus-1

clovus,

the prop will push wind backward facing either way. i made the mistake of having it on backward because the manual showed the adapter going into the prop, and then the prop going onto the motor in such a way that it was actually backwards. i made that mistake and broke my nose first launch as well as someone who posted on this thread earlier.

also ultrafly's ads do say that you should get unlimited vertical with the motors they sell with the su-27, so it might be worth redoing your wiring. or maybe its just false advertising, huh?

P.S. if your having power problems with the brushless i'd hate to fly that thing with the brushed 400 motor setup.