Cox PeeWee Micro Speeder

1/2A Nut wrote:Thank you Woody, for Cox engines I use premix 19% castor 2% synthetic.

Would be ok with a custom mix of 17% castor 5% synthetic to help flush more of the castor from the engine.

 

1/2A Nut wrote:The trick is to post the link using the youtube tab to display a vid on CEF.



Well done, more power today with the TD!

 

Top tip-
Set NV peak rpm with the plane level when using synthetic oil.
The steel on steel piston / cylinder overheats fast causing a on the
ground peak needle to be richer than needed in the air. Nose high
settings are not needed due to the thermal max state of synthetic oil.
With synthetic if the flight was rich lean the needle a bit, then start up
do not touch the needle quickly launch the plane before the engine reaches
top ground thermal state. The steel piston / sleeve will warm up quickly but
not die with the leaner setting on the ground if you launch soon as enough rpm
is being made. In the air the NV will be much closer to a good peak rpm setting.

Only castor can provide a better leaner peak needle on the ground with
moderate cooling changes in the air for a fuel mix that is only compensating
for the additional gain in unloaded rpm while flying. The engine more often
sings with steady top possible rpm in flights - not just by chance.

The art of a getting top rpm is understanding the imposed loading conditions on
the engine / design attributes and the effect of the fuel mix type / flight NV setting.

Can increase top end speed with back-cut on the CAM 4x3 prop while retaining some
of the thrust the 4 inch diameter prop provides.




 

Woody wrote:That was a good build log.
It flies real fast.
Should be called Ding Bat!!!
Congratulations on a great little model and also your flying skills.
At that speed you cannot afford to get disorientated.
The engine was nice as well. ( the full monte )

Woody wrote:Its a cracker.
Deffo a Dingbat!!!.
FWIW....on yer next fuse try rounding the nose to match the fuel tank diameter just to get that little bit  more less drag?
On the inside of the fuse at the nose, glue in four triangular bits so that you can then sand the corners away?
Only a suggestion.
You are more expert than me with a world record toboot?
I wish my reactions were fast enough otherwise I would build one.
I fly DEAD bats!!!!.

1/2A Nut wrote:-How much weight ready to fly?
-What is the wing span?

Well done, much better thrust to weight / improving rpm.
Up to 29,063 rpm brief peak pass 83 mph prop pitch speed / 134 kph.

With the current prop the engine can produce more rpm using a
ridged aluminum mount and turbo plug.

Can move the CG back using a radial mount.
Kamtechnik radial mount needs a 10 to 15ml nylon fuel bottle.
https://kamtechnik.com/product/ktk-02/

Allows a smaller fuselage firewall - dependent on fuel tank diameter.


Turbo plug adapter
https://kamtechnik.com/product/ktk-12/

 

Tobaiies wrote:

Woody wrote:Its a cracker.
Deffo a Dingbat!!!.
FWIW....on yer next fuse try rounding the nose to match the fuel tank diameter just to get that little bit  more less drag?
On the inside of the fuse at the nose, glue in four triangular bits so that you can then sand the corners away?
Only a suggestion.
You are more expert than me with a world record toboot?
I wish my reactions were fast enough otherwise I would build one.
I fly DEAD bats!!!!.

Thanks!
I thought of that at first, but completely forgot about it while building it.

Woody wrote:

Tobaiies wrote:

Woody wrote:Its a cracker.
Deffo a Dingbat!!!.
FWIW....on yer next fuse try rounding the nose to match the fuel tank diameter just to get that little bit  more less drag?
On the inside of the fuse at the nose, glue in four triangular bits so that you can then sand the corners away?
Only a suggestion.
You are more expert than me with a world record toboot?
I wish my reactions were fast enough otherwise I would build one.
I fly DEAD bats!!!!.

Thanks!
I thought of that at first, but completely forgot about it while building it.

If you so feel inclined Outer Zone plans would love this one.
Its a husband and wife offer to all modellers to gain free plans and I personally like to give back so it helps them and us.
You don't have to tell them your secrets of tuning.
That is undersatandable and okay.
Just the basic airframe with as much as you want to add.
The experienced flyers will love it.

Tobaiies wrote:

Woody wrote:

Tobaiies wrote:

Woody wrote:Its a cracker.
Deffo a Dingbat!!!.
FWIW....on yer next fuse try rounding the nose to match the fuel tank diameter just to get that little bit  more less drag?
On the inside of the fuse at the nose, glue in four triangular bits so that you can then sand the corners away?
Only a suggestion.
You are more expert than me with a world record toboot?
I wish my reactions were fast enough otherwise I would build one.
I fly DEAD bats!!!!.

Thanks!
I thought of that at first, but completely forgot about it while building it.

If you so feel inclined Outer Zone plans would love this one.
Its a husband and wife offer to all modellers to gain free plans and I personally like to give back so it helps them and us.
You don't have to tell them your secrets of tuning.
That is undersatandable and okay.
Just the basic airframe with as much as you want to add.
The experienced flyers will love it.

I would like to do it, but i have no plans. is a photo with dimensions enough or how does that work?
I'm not so enthusiastic about the flight characteristics, I'll probably build a new version.

Installed a small gps today and actually reached 129 km/h! I am amazed at how accurate these calculations are!
Tried another propeller (APC 4.1*4.1) and reached 158 km/h with no wind.
I think I'm on the right track, but I still have a lot of tinkering to do

1/2A Nut wrote:Good info, thank you for sharing  

What Receiver and GPS telemetry module are you using?
How much does the plane weight with GPS onboard?

Is it this RX and GPS?
RX is only 4.8g / 11g for the GPS worth the extra weight.


Note the rpm needed to do 158 km/h 25.3k rpm  


 

1/2A Nut wrote:Can you post a photo of the APC 4.1x4.1N?

https://coxengines.ca/cox-020/cox--020-piston-reset-tool.html

Cox .020 Piston Reset Tool / will be needing one of these.
Project engines should be checked set and ran up a bit rich.
After the first reset they tend to hold up very well with low drag
speed planes. Follow up with the next check after 1.5 hours of run time.

Time to check based on fuel mix, engine load from the prop and weight / drag of the plane.