Cox Fun Model .049 ... flight, flight and flight!!! (page 3 & 5)

Very nice! I started on one this spring...but having not built anything since the early 60's,I found I had to give up on it. Nowhere to get supplies around here anymore,and after 42 yrs. of turning wrenches I just don't have any dexterity in my hands anymore. , ....looking forward to a flight video!

rsv1cox wrote:Beautiful Mauricio.  How do you cut your circular holes?  Fine tooth hole saw?  Seems like a hole punch would distort the balsa.  

Bob

I use "new" sharp Forester bits or I sharpen the inside of brass tubing then using a Dremel cut-off disc cut small teeth at the sharpened end to make a cheap mans hole saw.

Hi Mauricio! I see some Sukhoi (SU26?) styling cues in that model.. Thank you for dedicating the model aircraft to us here! Another fine example of your modeling skills. It will be exciting to see you fly the airplane!

Amazing looking bird there Mauricio. Beautiful craftsmanship by you as always and something I always look forward to seeing.

Nice models vidéo edited like pro wit musique wawhouu no words To description of m'y feeling right now want To make video like that for m'y new rc cars prototype powered by cox engine like plane m'y self build couple scale look like never wit that hi level of perfection cant wait for flight video

Witch engine used ??the one wit rc ring single port wit no spi no 8 like gtp cylinder ??? Bit of cars flying

Thank you guys so much for stopping by and watching the video.
As soon as I have news of the flight I will also share it here.
Bob, here I am trying to explain the tools I use for the holes.
If the hole is less than or equal to 15 mm in diameter, I use a high speed steel drill bit and then finish polishing it, with a bur or with a round sandpaper using the manual lathe (Dremmel)
If the perforation exceeds 15 mm in diameter and more, I use my compass blade, which is seen in the photo. This compass will only be used for balsa wood and making a few passes depending on the thickness, up to 3 mm is very good, so if the thickness is greater than 3mm then I use my hand saw. This saw can be used on balsa wood, three-ply (plywood), pine and poplar wood, as well as some relatively soft metals and fibers.
If the work is even bigger, I use the bench saw.
I hope I have answered your question friend.




If I have to join two round holes to make an eyelet or oval type hole, (an adjustment), I heat this iron and put it at temperature I join the two holes, as you can see in the photo of the video in some ribs of the wings, where the servo cables pass.
(minute 1.15 of the video)

davidll1984 wrote:Witch engine used ??the one wit rc ring single port wit no spi no 8 like gtp cylinder ??? Bit of cars flying

I cannot understand clearly but I think I understand what you ask me, here is my answer:
It is the Cox .049 cylinder, which has a step and a single transfer, you have told me that it is number 8. The acceleration ring is commercial, from the ExModelEngines house - http://www.exmodelengines.com/product.php?productid=17629&cat=267&page=1
I plan to use some engines on this model, but initially starting with the Cox Babe Bee .049, I understand that it will handle it very well.
The model weighs 330 grams with fuel!

Very good work!

My Friend the Cox Fun Model .049 looks amazing I see you have the engine nose setting out from the cowl at good distance since having trouble with air flow on the other cowled engine . Good Fun !! Look forward to the Maiden flight .

Thanks Levent!
Thanks Eric! Yes, I did take into account the airflow in my Pitts model and I want all the traction of the engine to be truly available to achieve easy stunts.
I am hoping to have enough time to go to test, I am with my work in full and for that reason I will be a little delayed in the premiere.
In the meantime, and as it is a model designed for several Cox engine models, I will prepare my Cox .049 High Performance Engine "Black Lynx" that I won thanks to the courtesy of Cox Engines Forum and Ex Model Engines as a sponsor.
In the meantime I will make a detail of this engine to know it deeply.

Well, here I begin to prepare my brand new Cox Black Lynx .049.
I will be sharing my experiences with this engine.
As I want to know it in depth, I have made an exploded view of it to observe its parts in detail.
I also want to fit a throttle control ring.
Well, here we go with details and photos ...
I notice that the screw that holds the propeller is slightly twisted, so I must replace it.
When trying to fit the throttle ring or throttle control, it collides with the edge of the ports due to excess machining.
Trying to place the aero will damage the part, generating a scratch and leak, so I must place the cylinder on my lathe and smooth or clean that post machined edge.
I will also place a supplement thrust washer, in order to avoid the longitudinal displacement of the crankshaft, this allows to achieve better engine performance.
After doing those steps mentioned above, I will re-post the changes.
I like this engine! It promises great performance in advance!

Well, I have assembled my Lynx again, the throttle ring was perfect.
But there is a problem:
The hole in the crankcase is larger in diameter than the crankshaft, so the crankshaft does not have a correct adjustment.
What is wrong here?
The diameter of the crankcase?
or
The diameter of the crankshaft?.
This is not right, I will send a link to Mr. Matt to see what he can tell me.
I am attaching a video where you can see the exaggerated play between both parts, Carter and Crankshaft.

Mauricio, Matt already confirmed here what I also noted that the fit of most  anodized crankcases is rather loose on the shaft. Matt said that  in the new production run he will have the case bore diameter slightly reduced by the manufacturer which I could not welcome more.

Regarding the abrasion and wear of the anodization  by the starter spring, I prevent it by pulling a heat shrink insulation sleeve on the front of the case under the spring and shrink it by heat. It will stay fit and not allow contact between the spring coil and the anodized nose of the case.

Plus if they are using the Killer Bee crank specifications they are also slightly undersized for a looser fit. Tolerance stack-up problem. Try it with a babe bee crankshaft. The fit might be better.

Jason_WI wrote:Plus if they are using the Killer Bee crank specifications they are also slightly undersized for a looser fit. Tolerance stack-up problem. Try it with a babe bee crankshaft. The fit might be better.

These cases might be good candidates for Oilite sleeves.
Is there a machinist in the house?!! I have 2 KustomKraftmanship bushed
cases, but maybe that market has dried up.
BTW, I have the same engine. Maybe I"ll just swap
out one of those KK cases. They are black anodised.
Bob

Hi Mauricio, Why not swap-in (borrow) the bottom-end from another engine.. until you receive a replacement? Any decent/stock case-assy. will be able to handle your 16K max/rpm demand.

You may wish to "sleeve" the crankshaft-bore.. to save the defective case; seeing that you have the capability. It's been done.. (but not by me..   )

Most of my Cox engines are old ones.. I mean; original Cox Quality of the 1960's.. and the following decade or so.. You understand the quality of the Cox engines my friend. Look for Cox .049 Babe Bee and Golden Bee engines in your searches. These early engines were extremely well made.. as were the Medallion and Tee Dee series of that era.

András, Jason, Bob, Roddie:
Thank you very much for so much information.
In truth I was not sure whether to publish this point, it is not my wish to harm the product, but I want to collaborate so that another possible user can solve their problem.
It is not correct for such a product to be handed over to a hobbyist. If that hobbyist is a beginner and does not discover that there is a problem there, wanting to start the engine and it reaches high rpm can cause a serious accident.
Roddie, thanks for mentioning the quality detail. It is a shame, and I am somewhat devastated to know that some current products do not have and do not meet the quality of Cox products of yesteryear.
I am above all concerned that a product like this, under these conditions, could generate an accident.

I am going to evaluate what to do with this engine, for now I will put it aside since as I received it, it is not in conditions of use.

Helo just want To help save couple time for Good runing wit rc ring replace its Reed valve for methal or stainles rc ring acumulate presure inside crankcase wil diform Most valve Not made wit copper or stainles have jerobee engine is big différence wit regular throttle choke tube like sure start production engine for crank just use black widow texaco golden bee crank stunt engines dragon wil fit m'y self use of black crank case wit Difrent crankchaft inside no trust washer y dont recommande use of ring on that type of engines as is possible modification wil have the engine performance reduced rc ring is différence slot size y dont se wy use of black lynx wit rc ring try normal bee bee tank back plate use it as heatsink change Reed valve for copper or stainles use no8 cylinder wit hi compression head wit two gasket je picturs of modified tank wit remote Line heatsink modified

Sample of old black crankcase used for test wit aluminium piston wit plated cylinder y used mufler To reduce rpm y found aluminium piston friction inside cylinder wit very hi rpm now just Perfect for 6x3
Test Not finish 3 tank run from the mufler modification last run wit no sing of black stuf matériel from cylinder and piston seting it have Good compression now the particular cylinder has sufer from sand ingestion its wy is plated now its like al scratch inside filed wit matériel from plating inside look like scratch is différence in color

roddie wrote:

You may wish to "sleeve" the crankshaft-bore.. to save the defective case; seeing that you have the capability. It's been done.. (but not by me..   )

 

ohhh Roddie has inspired me !!!!
A special thanks to Roddie for the idea!

Nice work! Looks like a strong runner.

VERY nice work Mauricio!!

I am impressed

What kind of material is the new bearing?