Tomahawk-Design Bae Hawk 1: 3.5
#1251
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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?
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?
#1252
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Fill us in David. Thanks
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.
I will write a description when I have a little more time.
David.
#1253
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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.
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.
#1254
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 !
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.
#1255
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.
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.
#1256
Thread Starter
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?
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?
#1257
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
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.
#1258
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.
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.
#1259
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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
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
#1261
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
http://aerosociety.com/Assets/Docs/Publications/The%20Journal%20of%20Aeronautical%20History/2013-01_HawkStory-Fraser-Mitchell.pdf
#1262
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.
Thanks again,
David.
#1266
#1267
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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
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
#1268
Join Date: Nov 2003
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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.
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.
Last edited by erbroens; 05-08-2016 at 06:09 PM.
#1270
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.
#1275
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
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