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Tomahawk-Design Bae Hawk 1: 3.5

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Tomahawk-Design Bae Hawk 1: 3.5

Old 02-11-2016, 04:29 PM
  #1251  
Mike Pascoe
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Hi Jeff,
What size life battery (MAH) are you using on the gear? I've been experiencing some issues with mine and just had a 1100mah life pack made. I was told upping the voltage should solve my problems. I have the xicoy lg13c controller. I've cycled the gear many times in a flight and even after three flights It seems to only use a few hundred mah. Does this match what your seeing?
Old 02-11-2016, 06:48 PM
  #1252  
Mike Haddox
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Fill us in David. Thanks
Originally Posted by David Gladwin
I had lunch today with a very experienced and highly qualified engineer who was deeply involved in wind tunnel testing of the Hawk. We discussed pitch down problems and he gave me an explanation, nothing like any of us guessed might be the cause.!
I will write a description when I have a little more time.
David.
Old 02-11-2016, 06:55 PM
  #1253  
jws_aces
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Mike I am using a Zippy 1800mah 3s 9.9v life that was designed for TX from Hobby King. I call fly 3 to 4 times in one day and it might use at the most 200 to 400 milliamps on recharge. They are very inexpensive and I have 4 of them that have never given me a single problem.

I know I have flown more that 6 flights before recharging and it still had plenty left.

I just rotate them out along with my 2100mah 9.9v life for turbine at the same time with batteries that are fully charged.

Now I am using the Down and Lock controller but I am sure they draw about the same.
Old 02-13-2016, 02:39 AM
  #1254  
David Gladwin
 
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O K here's what I learned, Dr David King, former chief inspector of accidents at the UK AAIB was the guest speaker at our country club aviators group and I shared a table with him for lunch. We had some long and deep discussions. At the end of his visit I discovered he had been involved in wind tunnel testing of the Hawk. After the pitch down with flap problem was discovered, it was found to be caused by a vortex , originating at the intakes, interfering with flow over the stab. ( This also occurs on some airliners, many including the a320 I have just flown on have a large strake on the cowling to control this vortex) . The boffins came up with the idea of creating another vortex to counter this by removing the outer 15 inches of the flap vane. exactly how this worked we did not have time to discuss, except that later Hawks had full length flap vanes, but SMURFs were added just ahead of the stab. To stabilise airflow over the stab. Both fixes worked.

The Hawk was extensively evaluated by Boscombe and CFS and would never have been approved as a trainer if it had any nasty tendencies.

Myown limited experience of the Hawk is that it is truly delightful aerplane, a cross between the Gnat and the Jet Provost.

Although we are operating our models at very different Reynolds numbers, ( the relationship between air viscosity and dimensions of the object over or through which the air is flying) I have been very careful on all of my Hawks (2 Airworld and one Skygate). To very carefully replicate the wing dressing, ie vortex generators, fences, and the correct settings of the flap vanes, the inner section being removed as full size.

I have not yet flown my SG but both of my aW Hawks have flown a lot and have absolutely no vices,
max flap angle us about 45 degrees and only a littel up stab. Trim is needed to counter the slight nose down pitch when flaps are extended,

They show no sign of departure when taken to the stall, clean or with flap.

Thats all I know !

Last edited by David Gladwin; 02-13-2016 at 02:45 AM.
Old 02-13-2016, 03:33 AM
  #1255  
darryltarr
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Exactly David and well said, hope you are keeping well by the way.

The Boeing 767 and 777 also have the strake/vortex generator on the engine nacelle (top inboard), and it is known as the CHINE. Should this be missing then dispatch is allowed under the MEL/CDL but the penalty (provisos), is that you have to increase the VREF by several knots (obviously to avoid the unwanted separation that occurs at slow speeds with flaps extended).

Unfortunately I had an "out landing" with my Skygate Hawk (failsafe with turbine set to shutdown and gear set to extend), so I'm busy modifying and repairing the wheel well areas as the landing in the soft sand ripped everything off.
Old 02-13-2016, 05:02 AM
  #1256  
Remco45
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Hello David,

Thanks for the heads up. Just so people don't get confused: you write about your own Hawks: "...the inner section being removed as full size." but I assume you mean the outer section just as you mentioned in the first part?

@Daryltarr: sorry to hear that, do you know why the failsafe engaged?
Old 02-13-2016, 05:44 AM
  #1257  
darryltarr
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We have been having a lot of interference issues recently (over the last 3 months), at our club "RC Dubai".

https://www.facebook.com/RCDubai/

It seems to affect JR (DSM-2), and Spektrum the most (and please guys, I don't intend to start a brand war), Futaba FASSTest has experienced by far the least, and JETI is bullet proof.

The issues, coincidentally, started to occur once a new Microwave Tower was erected and also the Wi-Fi at the Hobby Shop was commissioned (Ultimate Hobby have a Shop open at the field).

We are trying to arrange a Spectrum Analyser to get to the bottom of it. In my case I was using an original PowerBox with two RX's, so although I managed to have full control (once the RX's kept switching), my turbine did shutdown (as per AMA fail safe settings), and my Landing Gear was set to extend - which is what it did.

On another note about 5 years ago I moved from JR to Futaba 14MZ and 18MZ, but hadn't got round to changing the Hawk to Futaba as it was flying so well so also I didn't feel the need to.

Having said that there is no guarantee that the same scenario couldn't have occurred with Futaba - but as I mentioned before it has been more reliable.

I am very keen to try the New JETI DC-24 with "triple RF redundancy", and hope to do that very soon once it is released.

Regards,

Darryl

Last edited by darryltarr; 02-14-2016 at 06:42 AM.
Old 02-13-2016, 12:55 PM
  #1258  
David Gladwin
 
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Thanks Darryl, I' m very well and trust you are , too, and EK not working you too hard !
Yes the 7373, 757 and 767' also had these strakes as, I believe does the A330 and 340 etc. so it all makes sense, now, Sorry there was a typo, of course I did remove the
OUTER section of the flap vane as per the full size. Anyway the result is totally benign handling with no nasty tendencies although I have not tried to spin my Hawks (yet?, )
For what it's worth I considerably strengthened the landing gear bay area of my Hawks with cf plate and cloth and on my SG Hawk , I lined the gear bay to clean things up.
Hope yours is fixed and flying again soon.
Best regards,
David.
Old 04-15-2016, 07:37 PM
  #1259  
berthoud
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I am happy to report another Hawk has taken flight. Congratulations to my father Kim Foster for such a beautiful model. I am sure it will be visible at many events in the future!

We had two successful flights today that were otherwise hindered by the landing gear. We are using the standard Tomahawk E Gear with a 3s A123 2500 mah retract pack (electrodynamics) with the new Xicoy LG 15 controller. Unfortunately the left main would not retract. I upped the amperage to 3.5amps in the controller to no avail but perhaps it needs to go higher?

Scott
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Old 04-15-2016, 07:39 PM
  #1260  
berthoud
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Of course this picture was taken before the maiden and and he was smiling a lot more after the first flight :-).
Old 04-16-2016, 12:44 AM
  #1261  
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There's a Royal Aeronautical Society paper available here about the aerodynamic development of the Hawk:
http://aerosociety.com/Assets/Docs/Publications/The%20Journal%20of%20Aeronautical%20History/2013-01_HawkStory-Fraser-Mitchell.pdf

Old 04-16-2016, 02:36 AM
  #1262  
David Gladwin
 
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What a brilliant paper, thank you so much for finding it and advising us of its existence ! At last a very clear explanation of the missing section of flap vane !

Thanks again,
David.
Old 04-16-2016, 05:40 AM
  #1263  
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Congrats on the maiden. Lovely model

Roy
Old 04-16-2016, 03:22 PM
  #1264  
ticketec
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Originally Posted by David Gladwin
What a brilliant paper, thank you so much for finding it and advising us of its existence ! At last a very clear explanation of the missing section of flap vane !

Thanks again,
David.
Yes a fantastic article! I'm half way through reading it at the moment but very interesting!

thanks

dave
Old 04-16-2016, 10:07 PM
  #1265  
lavi rider
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Are these available painted in the mold and in ARF stage as the ones from CARF/Skygate now?
Old 04-16-2016, 11:00 PM
  #1266  
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57 flights...
https://www.youtube.com/watch?v=bF-T...&feature=share
Old 04-17-2016, 03:06 AM
  #1267  
MattyMatt
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Originally Posted by berthoud
I am happy to report another Hawk has taken flight. Congratulations to my father Kim Foster for such a beautiful model. I am sure it will be visible at many events in the future!

We had two successful flights today that were otherwise hindered by the landing gear. We are using the standard Tomahawk E Gear with a 3s A123 2500 mah retract pack (electrodynamics) with the new Xicoy LG 15 controller. Unfortunately the left main would not retract. I upped the amperage to 3.5amps in the controller to no avail but perhaps it needs to go higher?

Scott
Congratulations! Looks really good.
Old 05-08-2016, 06:01 PM
  #1268  
erbroens
 
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Flying for the RAF this weekend .. it has a jet central mammoth and a spektrum dx18 .. takes in less than 100 meters with 15 degrees flap and lands in 50 meters with full flaps.

Certainly doesnt look fast in the air.. I estimate no more than 200 km/h and is about scale speed. .even so is a nice plane. I enjoyed it.

Guess I would enjoy it more if it was heavier and with a more powerful engine.

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Last edited by erbroens; 05-08-2016 at 06:09 PM.
Old 05-08-2016, 10:13 PM
  #1269  
1moparman1
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I have over 30+ flights the retracts are tired. On this air show it will not go up anymore lol
http://youtu.be/T2gvhzP-izc
Old 05-08-2016, 10:58 PM
  #1270  
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I got to do a check flight on this one yesterday, other than wanting more aileron movement with all the stores, its a sweet machine. Owner Steve had initial gear issues which now seem cured using Jet tronic high Flow valves. JR 28X and Behotec 220.

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Old 05-09-2016, 01:43 AM
  #1271  
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Old 05-09-2016, 04:25 AM
  #1272  
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nice scheme
Old 05-09-2016, 06:11 AM
  #1273  
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+1, very nice! How'd it fly on the 220?
Old 05-09-2016, 06:32 AM
  #1274  
1moparman1
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Originally Posted by Dave Wilshere
I got to do a check flight on this one yesterday, other than wanting more aileron movement with all the stores, its a sweet machine. Owner Steve had initial gear issues which now seem cured using Jet tronic high Flow valves. JR 28X and Behotec 220.

Nice! I have the early jet tronic valves is he running one way check valves also? May have to change them out.
i got a Behotec 180 gold in mine
Old 05-09-2016, 06:46 AM
  #1275  
Dave Wilshere
 
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Even with the 220 i'd say it needs 'bullying' around the sky, it has no momentum (normal for big really light models-especially with the ship anchor amount of drag this one has :-) ) It's about right, I spotted for Steve on his first flight yesterday and talked about getting on the power early, its fine like that and did nice large loops.

I don't think he has one way valves, would need to check, I had little to do on the build other that supply some of the equipment

Dave

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