Just curious about the P-51 FM

[K_Freddie]

Surely you're not talking about a 'Low-n-Slow'/ or just 'slow' aircraft being hard to down ??

Somewhere .. sometime .. this rings a really Bad Bell

[K_Freddie]

The real problem comes with the 'ground hogs', inability to accurately work out what the pilot is saying.

The biggest obstacle is that the 'groundhog' is just not in the pit when the story happens. The pilot has to deal with many variables 'on the fly', and make decisions based on education and experience. For the 'un-educated' these decisions are almost 'natural' and not worth mentioning ??

[tango2delta]

I do not know if this counts but I fly scale P-51D models, I have 2 that is 82" and about 30 to 40 pounds and let me tell you this, if you even breath wrong they will stall. And if you take off before you get your airspeed up it will snap roll. A P-51 will not fly tail heavy, if the CG is not right it will never leave the ground, it will but not for long. Now my 80" P-47 flies like a dream. I think the P-47 was the best U.S. built.

[MaxGunz]

If your models are scale right down to the airfoil curves then there's a little problem right there.

It just took me 10 minutes to remember the name that goes with it, it's about the Reynolds number which changes for wings as they get bigger or smaller.

The same shape airfoil works differently with different scale wings. What worked great for a bird worked less well for airplanes made before 1920 though the Gottingen thick wing used on the Fokker DrI and DVII went a good ways to fix that. Going from about 10 meter spread down to about 2 meters is going to be subject to a measure of that. But -only- if the curve of the wing is kept to scale.

I am wondering about controls on your models. Are the rudder, elevator and ailerons all controllable? I know of smaller models that only do rudder and elevator.

I also wonder if your controls are channel per axis direct like was done since long ago or if it's one channel wireless computer communication with a microcontroller in the plane? There's pluses and minuses either way.

[horseback]

There's also the little matter of Center of Gravity; unless your models are scale weight in the right places, it will have an effect as well.

cheers

horseback

[MaxGunz]

When I built model airframes the procedure was to attach a string at the balance point and whirl the sucker around. That went for model rockets too, IIRC.

[tango2delta]

Originally Posted by MaxGunz

If your models are scale right down to the airfoil curves then there's a little problem right there.

It just took me 10 minutes to remember the name that goes with it, it's about the Reynolds number which changes for wings as they get bigger or smaller.

The same shape airfoil works differently with different scale wings. What worked great for a bird worked less well for airplanes made before 1920 though the Gottingen thick wing used on the Fokker DrI and DVII went a good ways to fix that. Going from about 10 meter spread down to about 2 meters is going to be subject to a measure of that. But -only- if the curve of the wing is kept to scale.

I am wondering about controls on your models. Are the rudder, elevator and ailerons all controllable? I know of smaller models that only do rudder and elevator.

I also wonder if your controls are channel per axis direct like was done since long ago or if it's one channel wireless computer communication with a microcontroller in the plane? There's pluses and minuses either way.

Yes, all controls work. elevator, ailerons, rudder and flaps. Even have to trim them out. They have air retract system for landing gear. When I say scale I mean 1/4 scale. I use a futaba T8FG Super TX/RX to fly them with. One is a Aeroworks P-51B the other is ESM ARFP.

[MiloMorai]

Does your model of the P-51D use scale control surfaces movement?

What airfoil does your model P-51D use?

[tango2delta]

Originally Posted by MiloMorai

Does your model of the P-51D use scale control surfaces movement?

What airfoil does your model P-51D use?

Yes, (scale control) I have that setup in my Radio. The airfoil is NACA Laminar-Flow. What I am trying to say is if my model planes fly like the real P-51D they where built for speed (Interceptor) and long flights. But in a dogfight you would surly have a bad day in a slow turn fight. It would snap roll in a flash and turn around and spin not even trying. The first time I flew my P-51D I did that same stunt in that video not intending to, I just got to slow in a turn and gave it some up elevator and boom. Almost lost it. That would be the one that is my pic at the left top.

[MaxGunz]

The NACA profiles used on the P-51 work for wings the size of a full scale P-51. They will work less well on a 1/4 scale model. The difference due to Reynolds number difference can probably be calculated by an AE.

During takeoffs are you keeping wings level with side-stick (aileron)?

There are wireless network devices with outdoor line of sight range 1 mile for about $35 ea full retail. They have 6 10-bit analog inputs to read sensors or instruments or stick axes and send the results. They have 8 digital outputs to turn things on and off.
You can control more than 1 plane from the same ground station if it's got a PC hooked to it. Even use PC game controllers.
You can get feedback from the plane, it has a wireless node and even its own I/O. How about a pitot sensor and a slip ball and gyro/accelerometer data? Do you think you could fly better with that?


XBee Pro ZB has 250kbps speed, that's almost 5x 52k dialup. I remember when we'd go online IL2 and set net speed at 28k and get good games. Our big problem was lag and with local wireless that can be almost none. Transmission is light speed at a mile or less, not bouncing off satellites.

The Pro ZB is the middle column.
http://www.mouser.com/ds/2/111/ds_xb...ules-19140.pdf