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Oct 10, 2019, 08:11 AM
Foam addict
4stripes's Avatar
Be sure to measure the installed thrust and wattmeter readings before to launch.
What is the weight with battery?
Good luck!
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Oct 10, 2019, 09:54 AM
Registered User
mustangwally's Avatar
Thread OP
It weighs 3.614Kgs including a 6S5000mA motor battery, (plus 10g if I fit the 'jet light'). Slightly less than my original estimate of 3.650Kgs but a little more than was looking achievable a fortnight ago.
Oct 10, 2019, 10:48 AM
Foam addict
4stripes's Avatar
Not bad!
Do you have any other higher wingloading jets to fly before this one? It might be a bit of a handful.
I still think it is important to hook up a scale and wattmeter to measure the installed thrust.
Oct 10, 2019, 12:20 PM
Registered User
mustangwally's Avatar
Thread OP
4stripes :- I have no other jets or EDFs so it will have to be a 'kick the tyres and light the fires' job with this one.

Below is a picture of my pride and joy, a Miles 'Hawk Speed Six' in its middle life, (60s, 70s & 80s), finish. The real thing is now flying as originally constructed in the 30s.
Oct 10, 2019, 08:26 PM
Classic jets rule
AIR SALLY's Avatar
So your going to want to start with a 3 min flight and see what is left. Hopefully you wont need WOT for the whole flight.
Oct 11, 2019, 01:36 AM
jofro
Quote:
Originally Posted by mustangwally
I've managed a bit of progress over the last few days. The Solarfilming is now complete and the nose is looking fine to me, (it's also a less creased attempt than the original). I fitted the taileron and all-moving fin servo actuating mechanisms and all are all zeroed and tested for direction with the chosen receiver. The battery hatch is fettled and awaiting a final C of G balancing to fix the motor battery location. I've decided to go with a 26v - 6v BEC instead of using a separate receiver battery, that weight saving should haul me back nearer to 3.25Kg. The flaps are still to hinge and couple up as I am now going with conventional push-rods instead of RDS units. Next job is to start 'flatting- off' the film covering before final assembly and panel lining etc. However we are off to Edinburgh this weekend for family celebrations so next week will have to do.
Hi Wall, looking at it from the "fairway point of view on the golf scale", as you mentioned in your post#50, no body would noticed if you did improve it by marginal wing extension.
Hook it up on the scale and let me know what it pulls static with that 6S set up. (As on pics bellow)
Oct 11, 2019, 05:00 PM
Registered User
mustangwally's Avatar
Thread OP
AIR SALLY :- Yep, that's basically the plan.

1/. 10% power on before trigger is released.
2/. Increase power as bungee is triggered.
3/. Increase to full power at lift off from trolley.
4/. If it flies then gain height in circuit.
5/. Start trimming after 2nd or 3rd circuit.
6/. Try to fly on a reduced throttle setting
7/. Lowish pass for a picture.
8/. Set up for landing, (timer set for three minutes).
9/. Overshoot if necessary and land.
10/. Pose for pictures.

Well, that's the plan anyway.
[There is a stage zero at stage 1/. minus 15 minutes, swallow two of granny's old qualludes.]

I don't intend to re-test the thrust output as I have no intention of re-engining the model or re-working the wings, if it won't fly then it will crash in the 'normal' way. Game over.

P.S. What is WOT?
Oct 11, 2019, 05:03 PM
Foam addict
4stripes's Avatar
Your lack of experience is more than made up for with confidence!
That is not a plan for success.
Get a friend to take lots of pictures before then video so you can figure out what happened after the crash.
WOT...wide open throttle.
Oct 11, 2019, 06:05 PM
Registered User
AntiArf's Avatar
Quote:
Originally Posted by mustangwally

P.S. What is WOT?
Obviously not the British saying "WOT!"
Good luck with the model, looks great.
Oct 11, 2019, 10:32 PM
Classic jets rule
AIR SALLY's Avatar
Wide Open Throttle......WOT
Oct 12, 2019, 06:06 AM
Registered User
Ianda217's Avatar
We know from the duct tests that you have enough thrust at 2800 grams. This is a thrust to weight ratio of 77%. I have re-run the Fancalc calculation using your final weight and have copied the results below.

Interestingly, the calculated thrust is very close to what you actually got from your ducts.

Now it's all down to the pilot, the weather gods and the aerodynamics!!!! (and the launch system and the .......)
Oct 12, 2019, 11:19 AM
Registered User
mustangwally's Avatar
Thread OP
union1; AIR SALLY; Ianda & Anti Arf. :- Thank you for your encouragement and advice, hopefully my plane will fly OK. But if it doesn't, then it's still OK, only my pocket will have been hurt in the making of this model. I have enjoyed most of the build, (planking yeuch), and whatever happens I will carry on aeromodelling, building planes which appeal to me.
Hopefully within the next few weeks there will be a window of opportunity for a test flight and be sure I will report back here success or failure.

Again thanks to all who helped.

Derek.

4stripes :- I'm sure that everyone has noted how your positivity shines through like a beacon, I bet you're the 'go-to-guy' at your club.
Oct 12, 2019, 11:26 AM
Foam addict
4stripes's Avatar
I do indeed wish you the best of luck however if you interpret my advice as negativity you are sadly mistaken. I only wish to help you achieve your goal.
Having had experience with the exact setup you use I shared my experience yet you ignored it.
I wanted you to verify your power so you could make necessary changes yet you ignored that too.
Helping others is high on my priority list but some simply have to learn everything on their own (the hard way).
That can be an effective way to move forward too but it just takes more time and money.
Oct 15, 2019, 03:54 AM
jofro
Quote:
Originally Posted by mustangwally
AIR SALLY :- Yep, that's basically the plan.

1/. 10% power on before trigger is released.
2/. Increase power as bungee is triggered.
3/. Increase to full power at lift off from trolley.
4/. If it flies then gain height in circuit.
5/. Start trimming after 2nd or 3rd circuit.
6/. Try to fly on a reduced throttle setting
7/. Lowish pass for a picture.
8/. Set up for landing, (timer set for three minutes).
9/. Overshoot if necessary and land.
10/. Pose for pictures.

Well, that's the plan anyway.
[There is a stage zero at stage 1/. minus 15 minutes, swallow two of granny's old qualludes.]

I don't intend to re-test the thrust output as I have no intention of re-engining the model or re-working the wings, if it won't fly then it will crash in the 'normal' way. Game over.

P.S. What is WOT?
Mate, your 10 point way to start with, above, is the wrong approach. You should always have the "full stick", ( that's how we say it down here) before release!!!!!! for successful launch. Keep it simple, the more you complicate things the more trouble you are asking for.
I have been bungee launching dozens of models of every variety for the last 20+ years, healthy ' kritik ' is always the best thing you can learn from.
PS, I know why you don't do such important thing as static thrust check as a fully complete project, because you'll never get 2.8kilo pull out of your 6S set up with those lousy intakes. Don't forget, this is an EDF model, not jet scale jet powered turbine one!
Last edited by jofro; Oct 15, 2019 at 04:01 AM.
Oct 15, 2019, 06:13 AM
Aka: Tom Jenkins
ApexAero's Avatar
That full stick works well for you when you have the balance wrong doesn't it!


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