Some TFModel Fenestron owners have had problems with the tail holding. I redesigned the blade profile in aluminium, added a thrust race to each blade - and also added an aluminium upgrade actuator mount....
Joel kindly tested my aluminium design in his 800 TFModel Gazelle. You can read about his build and testing here:https://rc.runryder.com/t731489p6/
Continuing on from Joel's tests of our new design fenestron blade and hub for the TFModel Gazelle. The new fenestron design has 2 normal radial ball races on each blade similar to the original TFM fenestron, but also includes a thrust race on each blade. The addition of the thrust race has made blade actuation much easier to achieve. The blade profile has also been changed. The blades have been machined from aluminium in an attempt to eliminate any possible blade distortion at high RPM. The blade mounting disc has been redesigned to accept the new bearing arrangement.
Joel tested the new blade design mounted on the stock TFModel fenestron blade hub. He achieved better air flow performance, but blade actuation was not good. While the aluminium blades are quite light in weight, they are about twice the weight of the plastic original â€“ blade actuation in this case was not possible at high RPM.
Testing of the thrust race hub with the aluminium blades was successful. Joel has done several tests and he is happy with the result.
You may be aware that having parts CNC machined is not a cheap process â€“ the more of each part machined in any machining run, the cheaper each part would be.
The main reason for this post is to see if there are any other TFModel fenestron owners who are having problems with the holding ability of the heli tail. I need to order parts for another fenestron and thought I would post here to see if there is any interest from any other TFModel fenestron owners in replacing their fenestron with the new thrust race aluminium version. As I said CNC machining is not cheap so the more parts I order, the cheaper the fan would be.
So If anyone is interested in getting a price â€“ please let me know so I can get a bulk price together. I understand TFModel has partially closed down â€“ is this correct? If they are still in operation, maybe they might be interested in contacting me and take on the new design themselves. I am happy to hand over to TFM, my 3D models. I really donâ€™t have time to make fans as a business â€“ I just need to put together another fan and thought we could help each other to keep the cost downâ€¦. Anyway, there are some photos of my Gazelle fenestron and parts below.
Also there is another part of the TFModel fenestron that I was concerned about and that is the mount for the blade actuator. I was not happy with the tiny screws into plastic so I had an aluminium version made. The new actuator mount is pictured as well.
As a guide, machine enough parts to make 3 fans, the cost is somewhere between $500 and $600 â€œper fanâ€ â€“ this includes 9 blades, 9 blade/bearing mounts, 1 main hub and 1 actuator mount â€“ all aluminium. Depending on bearing costs they could be included in that cost â€“ I need to confirm thisâ€¦
There is also some hole tapping M1.5, M2 & M3 â€“ these, I do myself.
There is also 1 â€œLEFT HAND THREADâ€ I also do this thread myself â€“ this is to attach the belt sprocket fitting to the blade hub which is a left hand thread.
The additional weight added to the heli tail by using the aluminium parts
is about 25 grams. As an example of what 25 grams is, my glasses weigh 27 grams.....