Spitfire

[GuyOReilly]

Okay,I do not have enough kits to build or projects on the go, now I inherited a Spitfire 2/3 built.
Of course it will be electric.  There are no plans, but the booklet is sufficiently detailed to allow completing the model.
Will decide if I put the Lancaster on hold and finish this one first, or the DR1, or....
Decisions, decisions, decisions...

[GuyOReilly]

A quick look at the tail and it looks scale to me.   
Perhaps I should consider a built-up one with more area for stability.
I would rather sacrifice scale for the benefit of safe flying.
Power plant would be a 3-4 cell 35 size motor.
Probably no retracts as the booklet does not provide much details on the landing gear placement. 

[Frank v B]

Guy,  re: tail section- oversize

A way to answer this question:

guideline- tail feathers on a model warbird should be about 15% oversized verses the real one.
method: calculate the ratio of stab span to wingspan from plans of the full size.  An exact scale stabilizer on the Mark 9 model is 28.8% of the wingspan (48.5") or 14.0".  This model's stabilizer span should be about 33.1% of the wingspan which is 16.1".

With the fin and rudder, I have increased the size of the fin/rudder by adding a 1/4" wide back edge (trailing edge) of the fin and 1/4" to the leading edge of the rudder.  Then cut off the top of the rudder (counterbalance) in line with the top of the fin and make a new counterbalance because it will be 1/2" wider.

FWIIW

Frank

[Andy Hoffer]

Okay,I do not have enough kits to build or projects on the go, now I inherited a Spitfire 2/3 built.
Of course it will be electric.  There are no plans, but the booklet is sufficiently detailed to allow completing the model.
Will decide if I put the Lancaster on hold and finish this one first, or the DR1, or....
Decisions, decisions, decisions...

Hi @GuyOReilly

Ask the guy sitting in the cockpit at the top of photo 7567.  He looks very sagely. 

Andy

[Andy Hoffer]

Guy,  re: tail section- oversize

A way to answer this question:

guideline- tail feathers on a model warbird should be about 15% oversized verses the real one.
method: calculate the ratio of stab span to wingspan from plans of the full size.  An exact scale stabilizer on the Mark 9 model is 28.8% of the wingspan (48.5") or 14.0".  This model's stabilizer span should be about 33.1% of the wingspan which is 16.1".

With the fin and rudder, I have increased the size of the fin/rudder by adding a 1/4" wide back edge (trailing edge) of the fin and 1/4" to the leading edge of the rudder.  Then cut off the top of the rudder (counterbalance) in line with the top of the fin and make a new counterbalance because it will be 1/2" wider.

FWIIW

Frank

Hi @Frank v B ,

You mean FWWII (from World War II), right??! 

Andy

[GuyOReilly]

Guy,  re: tail section- oversize
A way to answer this question:
guideline- tail feathers on a model warbird should be about 15% oversized verses the real one.
method: calculate the ratio of stab span to wingspan from plans of the full size.  An exact scale stabilizer on the Mark 9 model is 28.8% of the wingspan (48.5") or 14.0".  This model's stabilizer span should be about 33.1% of the wingspan which is 16.1".
With the fin and rudder, I have increased the size of the fin/rudder by adding a 1/4" wide back edge (trailing edge) of the fin and 1/4" to the leading edge of the rudder.  Then cut off the top of the rudder (counterbalance) in line with the top of the fin and make a new counterbalance because it will be 1/2" wider.
FWIIW
Frank

@Frank v B thank you for this explanation, very useful.
I know that if the stab is less than 15% of wing area you are just asking for trouble; I will calculate/approximate the surface areas and see where that falls with the suggested 16 inches span for the stab.
I was planning to make a built-up structure (not a slab of wood) for the stab-elevator and fin-rudder.  It should be much lighter.  The L/E and T/E would be laminated from 1/16 balsa, possibly 4 to 6 layers then sanded down.
I am unsure about the size of the rudder still, adding only a 1/2 inch all around seems low.  Perhaps 1 inch all around might be better?
I will keep you posted.
Perhaps the Lancaster can take a backseat...

[Frank v B]

Andy,

re: FWIIW

For What It Is Worth..... in your case.... not much.


Frank

[GuyOReilly]

As I am no expert with elliptical wings are calculation, I approximated the total area as somewhere between 414 to 475 square inches.
I also looked carefully at the the instruction booklet and noted many interesting facts about this model.
- It has no landing gear by design.  Nope, none, no reinforcement, no material provided, nothing.  Hand lunch it is.
- The wing is sheeted and I have to cut the 10-inch ailerons by sight, with a ruler.
- The motor mounting is straight forward; a box mounted on the firewall.
- The battery installation is also easy, should fit a 4 cells no problem.
- The removal of the battery will require the removal of the fuselage.    There are no access hatch provided and the battery is mounted in a box that forms part of the fuselage structure.
- The stab and elevator will be built-up.
- The fin/rudder could be fixed, no rudder servo, no linkage, simple.  @Frank v B question for you: To rudder or not to rudder?
- The fin is three parts as per the instructions: centre piece of 1/32 plywood between 2 pieces 1/8 of balsa, sanded to shape.  Heavy!
- The instructions even suggest that it could be a PSS.  It is light enough, but no hills or ocean cliff nearby.
- For the covering, the manufacturer suggests dope and tissue.  That must be an old kit...

You will see in the attached picture the intended increase in the stab/elevator and rudder/fin.  The rudder may be a little bit to high and will probably reduce the height by 1/2 to 3/4 inch.

[Frank v B]

Guy,

To rudder or not to rudder. If it is hand-launched there is no real need for a rudder but I would put one in since it is easy and servos are cheap.
Two reasons: 1) it gives an extra way to trim the plane (to take out building error), and; 2) it allows you to do extra aerobatic moves (hammerhead stall, etc.)

I probably have 10 hand-launched planes that do not have rudders (Tucano, Nooner, Fox).  They are mostly Speed 400 planes and they fly fine.  This plane is larger and and can be flown more accurately with a rudder.

The plywood in the center of the fin/rudder is not required.  I would build it without the plywood and a total thickness of 1/4 is more than strong enough.  That is the same as the stab on the .40 size Skywriter club build project.  Most of us ditched the plywood.

I don't know if it is worth building open structure tail feathers.  I would use the solid tail feathers and add power on the front end.

Frank

[Andy Hoffer]

Guy,

To rudder or not to rudder. If it is hand-launched there is no real need for a rudder but I would put one in since it is easy and servos are cheap.
Two reasons: 1) it gives an extra way to trim the plane (to take out building error), and; 2) it allows you to do extra aerobatic moves (hammerhead stall, etc.)

I probably have 10 hand-launched planes that do not have rudders (Tucano, Nooner, Fox).  They are mostly Speed 400 planes and they fly fine.  This plane is larger and and can be flown more accurately with a rudder.

The plywood in the center of the fin/rudder is not required.  I would build it without the plywood and a total thickness of 1/4 is more than strong enough.  That is the same as the stab on the .40 size Skywriter club build project.  Most of us ditched the plywood.

I don't know if it is worth building open structure tail feathers.  I would use the solid tail feathers and add power on the front end.

Frank

Hi @GuyOReilly ,

I can't imagine doing a forward slip on a proper (aligned with the runway) cross-wind landing without a rudder!!! 

Andy

[Frank v B]

re: Andy's "I can't imagine doing a forward slip"



F.

ps: 9 out of 10 cartoons were backward slips.

[Andy Hoffer]

Bien sur, @guy. bien sur.

Touché!! 

Andy

[pmackenzie]

If this is the 48 1/2" span BalsaCraft kit, I have the plans for that, plus photocopies of some of the sheet wood parts.
Yours if you want it, and can pick it up from me in Don Mills.

edit - for sure it is the same one. I have the same manual you showed in one of your images.

Pat MacKenzie

[GuyOReilly]

@pmackenzie WONDERFUL!!!
Thank you.  Please let me know when it would be convenient for me to pick the plans up.
I am so HAPPY!!!
Guy

[GuyOReilly]

More progress.
The engine mount.