Warbirds Replicas P51 Mustang

[RICHARD WILLS]

1 hour ago, Gordon McConnell said:

Congratulations Jonathan, great to see you first flight achieved safely. Your model looks terrific! 

I finally got my P51 to the flying field today in good conditions. My intention was to do some high speed taxy runs as our strip is narrow, with rough mowed grass and a longer grass border. I found it very difficult to  keep the direction straight down the centre of the strip, having some big swings in yaw running into the longer grass. I have a fixed tail wheel and I played around with the rudder travel and expo to reduce the sensitivity. I held in full up elevator to keep the tail wheel firmly  on the ground. I got better at it but still not confident to accelerate under full power to take of speed. 
Has anyone had this sort of controllability issue and how was it managed?

I would be grateful for any advice you can give. 
Thanks. 
Gordon

 

Gordon ,  It sounds like you might be under a lot of pressure with your test flight in such conditions . 

Personally I would try to re adjust the odds.  Trying to steer down a narrow runway with tall grass either side and a new and precious model is not a good idea . Not only that , but while the temperatures are this high , the air is very thin and the flying surfaces will stall prematurely . 

Firstly , wait till the air cools a bit or maybe think about early morning or late evening . Choose a day when the there is a light breeze of around 8-10mph . As you have long grass all around , how about tucking the wheels up and asking someone to launch into wind ? If you use a 2 blade prop the torque will be drastically reduced , but even with the four blade , a 3/4 power launch should be fine . Just dial in a little right aileron and ask your launcher to aim slightly right of the winds eye . When it comes to landing , make the long grass an asset and simply pancake, wheels up , into wind on the long stuff. 

Once you have the model trimmed and realise how benign they are to fly , your take off issues will sort themselves out . 

Like you , I would fix the tail wheel , but I would reduce rudder throw to the minimum once i have established that the models runs straight . 

See , I'm not crazy all the time ?

[Jonathan S]

Hi, 

I will give the esc another programme and see if that works. 

 

Must say it flys so well. I was scared on the maiden after 1.5 years of work on it but it was a pussycat like a trainer.  Looks fantastic in the air. 

 

It was a windless day so landings were fast.  I somehow bent one of the landing struts, but it bent forward which is odd.  Quick fix I hope. 

 

Gordon I did a few taxi runs and she did move, I went with lots of rudder and she kept straight on take off could have done with more on landing though I would go with almost full rudder but 30% expo.  

 

[RICHARD WILLS]

I dont think we can underestimate Jonathans achievement here . For us "old timers" it is hard to go right back to the beginning of our balsa bashing journey , and even then , if we are honest , the final result was nowhere near as scale or realistic as the models shown here. We also saw David on the Spitfire thread , building and test flying (well , he wisely got the club expert to do that ) .  Newbies are as rare as hens teeth and it shows how nice our little group is that we can all chip in and keep those with less experience on the right track . 
Im not sure where we go from here given the current financial climate and this probably isn't the right place to discuss it . But perhaps when the autumn comes , we can all have a little conflab about doing something together . Maybe going backwards to a cheaper and simpler model ? 

[gillyg1]

Yeah sounds like a plan,

Was well impressed  with the standard of finish Jonathan, well done 👌😉

[Gordon McConnell]

Richard,

I agree totally with what you say. Jonathan has done an amazing job to build his model and have a successful flight. I think your and the the other key guys support for this forum topic has been the key to my successful build and to Jonathan’s as well. Many thanks to all of you. 
I will take your good advice on reducing the risk on flying from my strip. Weather is not quite so hot up here and we always have a breeze ( at least!). Paul’s advice on being very progressive with the throttle advance is a good one. 
Richard, the max rudder travel is quoted as 30mm. Where is this measured? Is it at the top of the rudder or elsewhere? Best to start off with the correct travel to begin with!! 
Also your point on another project is very welcome. Winter is not too long away!! 
All the best, Gordon

 

 

[Jonathan S]

All,

I do have to thank Richard for designing an amazing plane that a beginner can build and fly.  It flys so well.  

I also have to thank Paul, Eric,and the rest of the guys who have helped and encouraged, without you guys I would not have a flying model. 

 

So big thank you guys. 

 

 

[Paul Johnson 4]

Jonathan maybe a Spitfire next? 😉

[Jonathan S]

Paul,

I am planning it for the winter.... its on the shelf ready to go. Just need a month or 2 break before I get going oh and build the foamboard Mossie.  

 

 

[Eric Robson]

Jonathan ! I thought that foam board Mossie would be well on the way by now, they are ARTF.

Great job on the P51.

[RICHARD WILLS]

14 hours ago, Gordon McConnell said:

Richard,

I agree totally with what you say. Jonathan has done an amazing job to build his model and have a successful flight. I think your and the the other key guys support for this forum topic has been the key to my successful build and to Jonathan’s as well. Many thanks to all of you. 
I will take your good advice on reducing the risk on flying from my strip. Weather is not quite so hot up here and we always have a breeze ( at least!). Paul’s advice on being very progressive with the throttle advance is a good one. 
Richard, the max rudder travel is quoted as 30mm. Where is this measured? Is it at the top of the rudder or elsewhere? Best to start off with the correct travel to begin with!! 
Also your point on another project is very welcome. Winter is not too long away!! 
All the best, Gordon

 

 

Gordon , I have 30mm of travel either side at the most rearward point . ie pretty much in line with the fuselage centre line . 

However , as I fly mode 1 , I try to keep rudder throw to a minimum as I use the left stick for my elevator and its easy to keep nudging the rudder .  Mustangs generally roll straight . So test it by just pushing down a tarmac road . 

After that , remember that it may be best to start with perhaps half right rudder . Once it gets rolling after about 30ft you can ease off as she will probably go straight. 

[Gordon McConnell]

Thanks Richard. Will set the rudder up as you say and test that the model tools straight. Will lilkely have another go at high speed taxi this afternoon. 
Gordon

 

 

[Gordon McConnell]

I had another practice taxi test today at the field. The wind was moderate  to gusty and the direction was from the south which meant using the short er runway but at least the wind was right down the runway. 
I had earlier checked that the model ran straight on a tarmac area. The rudder travel was adjusted as Richard suggested. 
Putting on half rudder for the first taxi run made it much easier to control. On the second run I managed to keep it down the middle and made the decision to continue the take-off. She flew off perfectly with only some right aileron trim needed. The gear retracted ok and soon it was time to think about the landing. I dialled in some flap expecting a trim change in pitch but none needed and in fact there seemed to none needed with full flap which was a pleasant surprise. Landing was affected a bit by the gusts but helped by Paul’s advice to keep some power on. 
Absolutely delighted to find such good flying qualities and to have finally completed the first flight! 
Thanks to all on the forum for the sharing of tips and advice and to Richard for such a fine design. 
Gordon

P.S. the sheep were trespassing on the other runway. 😀😀 

[Paul Johnson 4]

Well done Gordon  I bet your grin was ear to ear 

[Gordon McConnell]

Thanks Paul. The grin was even wider than that!!! 😀😀

it is very satisfying, after hours and hours of work to build a model, to have a very successful first flight. But this one was special for sure! 
Gordon

[Graham R]

Well done Gordon.

[RICHARD WILLS]

Great Job Gordon . Shaun and his friends didnt seem very impressed though . 

I can't imagine what you are going to do with yourself now though .😁

By the way . As the rest of your club are not building inclined , couldn't you sell it to them at ARTF (wooden ) price ?

Probably be about £500....

[Gordon McConnell]

No way! They can remain envious!! 
Interestingly showing the model on our What’s App group has sparked interest in having a warbirds day or a scale day at the club. A few of the members do have kit built models so hopefully it will encourage others to try to build a kit or plans pack model. 
wondering what to build over the winter. Anymore warbird kits on your shelf or in future Richard? 
Best, Gordon
 

[Paul Johnson 4]

Gordon he might just have a spare Spitfire kit...

[Paul Johnson 4]

 

[RICHARD WILLS]

Ive got Some Spitfires and a single rare Ju88.

[Gordon McConnell]

Richard, I have sent you a PM. Gordon

[RICHARD WILLS]

Hi Chaps , Just a little tip here . The grass runways are becoming very hard and even if you make a smooth landing ,you can still endure some serious jolts as your model slows down . These impacts can be tolerated by a foam veneered wing , as the foam acts like a giant shock absorber . 

However , laser cut wooden wings ,as on our P51 and Spitfire ,provide a very rigid mount for the retracts . 

There is a very simple way to decrease the odds of you wrecking your mounting plates . 

You simply slacken off the four self tappers and trap a piece of silicon rubber underneath the plastic retract plate and the plywood mounting plate . This , to some degree , dissipates the shock and replicates what happen in a foam wing .

Paul has done quite a bit of experimenting , which was necessary because he chose to omit my recommended 8swg coils .

We have discussed it .........

He was quite rightly sent to the naughty step. Even at six foot three .

[Paul Johnson 4]

I'll have you know its 6'4" old chap.... every inch counts 😜

 

I use 6mm silicone rubber sheet  cut into two strips with clearance holes for the screws. Just nip the screws till they just start to compress the silicone.... works a treat.

[Bruce Collinson]

Can’t resist asking; source of suitable tried and tested 6mm silicone rubber sheet?
 

BTC

[Paul Johnson 4]

 

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