Cox prop question

Boy, I don't know that is a lot of pitch.

According to the manual, the sky-copter used a 4.5x2 prop.



Do you own the mold or is it being offered to you for sale? What would be the smallest run you could make to test the market with?

This prop sounds more like a speed prop for the .049 mousers.

There is one thing you could check Bernie. If there is a "pin" in the mold for forming the hole in the hub for the prop-screw.. ask if it can be measured. If it's .104" in diameter (2.64mm) then it's a mold for an .020 (3-48 prop-screw) If it's .128" (3.26mm) then it's for an .049 (5-40 prop-screw).

That would be good prop size for a TD .049 on a combat plane. Ken

Found mention of that prop here, but it's a pusher.
http://www.rcuniverse.com/forum/1-2-1-8-airplanes-70/8969340-what-models-did-cox-use-prop-om.html
Question, but no answer.
Bob

VUgearhead wrote:This prop sounds more like a speed prop for the .049 mousers.

I was thinking the same thing too. Its likely a competition prop.

Could actualy be the 2D x 2 1/2P for a .020

Here is the prop and chart from a cox prop package

Quite sure that it's an 020 prop but the fellow likely typoed the size and it is probably a 4 X 2.5; which is a Cox .020 speed prop.

The mould is not for sale and is owned by an outfit that used to mould for Cox. They have made many prop for us, including our 4.5 X 2 props in black and grey.

We are trying to get clarification as to the mould as well as its condition and, if everything pans out, shall make run a couple of thousand.

The rpm reads:
17.2k just prior to launch
18.6k right out of the hand
20.3k best level pass
Makes good thrust / no fuel pressure feed solid feel tracks good climbs out with ease on this prop.


Thank you Bernie fingers and toes crossed!!
If you folks want to see how the prop performs on a stock TD .020 check out my vid. 21in wing span / 3ch Lil Speedy.

 

Man, that little thing really scoots! Thanks for the vid.

If the mold is for a 4Dx2.5P prop that is what came on the Lil Stinker, Red Barron, Pits Special and the others and is very hard to find even on eBay.

Yes that is correct is what I told Bernie - I asked him to carry this prop as it will make any Pee Wee or TD .020 come alive and still provide good thrust.

I have done a lot of prop reworking and find this one to be a great overall mix of thrust and speed in comparison to the 4.5 x 2p for those who wish they could add more pep to the .020. The bore is for the .020.
A single port .049 reedy would be safe to run on 15% and scream like you always wished it would.

Hi Bernie any word on the prop mould?   

Last week, the fellow said he would pull the mould and make a putty sample to take pics of. Have not heard anything further, but running a few 1,000 props is not that company's biggest priority. They usually make runs in the 100,000's. His dad used to run / manage Cox in the 70's and the only reason they even humour our requests for small runs.

dckrsn wrote:I'll take a stab, and guess the .020 Sky Copter.   
Bob

4.5x3p is the best I can see on mine worn one

Cox International wrote:Last week, the fellow said he would pull the mould and make a putty sample to take pics of. Have not heard anything further, but running a few 1,000 props is not that company's biggest priority. They usually make runs in the 100,000's. His dad used to  run / manage Cox in the 70's and the only reason they even humour our requests for small runs.

  That sounds rude but at least there is something there that seems to ....CLICK.. there are us people out there that still are very involved in this community and I would like too say wee THANK YOU!!! Eric 

Nah, it's business from the vendor and quite understandable.

Factoring in initial machine set-up time and a run of a couple of thousand, there is likely little, if any, profit in it for the shop. At least not at the pricing they charge us per-piece.

Their moulds runs semi-automated 24 hrs / day and they are so booked with work that they are acquiring a new building and machine park. When they pull a machine from their almost non-stop service, they are doing us a favour because more lucrative work gets delayed.

They are really nice people but have to fit us in between jobs and that can often take months.

Thank you for your efforts we will just have to cross our fingers and hope for the best that company has some spare time soon.

Ok, it has been confirmed that the mould is for 4D X 2.5P and they will be moulding us props in about 2 weeks.

Black for now as the grey resin is a special order but, the next time we order other prop sizes in grey, will have those also moulded in grey.

Steve (the owner of P-Plastics) knows that we appreciate his support.

He will run a few 1,000; whereas we have to take 1,000 at once.

You guys said that the prop will be a "hot seller" so, when available please show this by buying them

We have quite a few "hot products" sitting here that we were told would sell well and .... we still have enough to last lifetimes lol

Fantastic News Bernie!!!!       

This is a very very rare prop that most of us had given up on ever seeing in production again.
The prop was fine tuned by Cox back in the day to help hop up the PEE WEE and TD .020's
That prop was an absolute must for a line of various PEE WEE powered CL planes allowing the development of a whole new world of miniature performance flying planes sold during that time.  Lable its significance when setting up the web page for it.

I too will be buying bulk lot of them for .020 CL and RC planes I have hoarded over 10 Pee Wee's and have 8 TD's. With the advent of the light weight micro RC gear the humble Pee Wee and TD .020 have been back in action! What they had lacked was the right prop specially made for performance flying being flexible and durable enough to last a reasonable amount of ground bashing. This prop will inspire new creations and revive old sluggish flying ones.