tubig

Took 5344 to the field a couple of days ago for taxi tests. Discovered a problem with the rudder/tail wheel linkage so didn’t get far. Repositioned the rudder servo to solve the problem (I think). A friend took a short video of one of the taxi’s.

tubig

5344 has maidened. It wasn't a total success as there was too much speed on landing causing a bad bounce and a subsequent hard landing causing one of the legs to collapse. But the problem has been solved and she's ready to go again.

Also, got a start on the spinner. Made from .060" plastic on a 3/16" backplate. More to do.

carlgrover

How did you make that spinner?

carl

tubig

Carl, I used the aluminum spinner that I bought with the plans as a form for vac-forming the spinner.





The backplate is 1/8” ply with hard balsa mounts.



Screws are #2 x 1/2” sheet metal screws.



I must say that this is the first time that I have tried making a spinner and I may completely redo it or even abandon it. At this point I am having difficulty resolving a vibration problem at any speed other than idle. While the spinner looks concentric it’s not completely concentric and that is becoming a problem.

carlgrover

Thanks for posting up the procedure. I've done a lot of things including vacuum forming but have yet to try a spinner. Did you balance the spinner by itself? I've been told that on the Platt 109 you have to balance the older style spinner alone then balance the prop separate. You also have to keep the rpms down as low as possible for the same vibration issue. Of course that spinner is twice the size of yours.

carl

tubig

Yes, I static balanced it but just the spinner without the prop attached (not possible for me to do that). As it turns out some of the runout in the spinner is actually coming from runout in the prop adapter. I tried but could not get rid of the runout in the adapter so will have to live with it.

Did high rpm spin tests with prop and spinner attached on an arf. Ran the motor to 6000 rpm for 15-30 seconds several times. There is some vibration but less than an ic engine and not destructive in my opinion. Afterwards, all screws were still tight and no deformation of the plastic noted. I feel comfortable enough with it to try some inflight testing with the spinner as is on a beat up 109 arf before committing to the BT.

Slidexx

Hi Guys, Quick question,On the plan the firewall has some up thrust on it. Have not seen it on any thing else I have. Do we stick to the plan or not.
cheers Allan

Ricksey007

Does anyone know if Unitracts are still in business? I have tried to contact them with no response.

Sean

tubig

Sorry that I missed your post Allan. Apparently, I didn't get a notification.

To answer your question, when I originally built for a glo engine I followed the plan. However, I don't remember the thrust angles that are incorporated into the plan. When I modified the model for ep I rebuilt the firewall with 0/0.

tubig

Sean, my understanding with Unitracts is that it is still in business with a new owner who is a one-man show. That being said, sometime ago I emailed him to inquire about retracts for a BT Mossie but never received a reply.

johnboy151a

My Feedback: (68)

I got the retracts for the BT typhoon from them about 3 years ago. That was my only attempt at working out with them. If I remember correctly, they took a while to respond.

Slidexx

Thanks for reply, We have decided to go 0/0 cheers Al

eromeros

Hello tubig , your MEBF109 looks great. Could you please measure the overall width of the cowl?

Thanks

Ricksey007

eromeros,

I measured my fibreglass cowl at 153mm (exactly 6"0 at the widest point, just where the exhausts will mount.

Sean

eromeros

Thanks Ricksey007

tubig

It has been brought to my attention that the photos in this thread are missing, and sure enough, they are. I don't know the reason and it would take far too long to re-submit them.

For those that are still perusing this build, you can find the same build (with photos!) here: Bf109E-4, W.Nr.5344

Tim