Another Sensei Repair - with pictures

[Billyboy46]

Hi although I'm not a TEMAC member I appreciate reading your forum and thought that I should contribute and not simply lurk here.

A couple of weeks ago I crashed my Sensei over at Claremont (glad to know I'm not the only person learning on a Sensei locally). 

I did some dis-assembly at the field in order to see how bad the damage was. Fortunately, the cowl broke away almost intact, and the nose and motor mount broke off without bending any metal pieces - I wasn't sure about motor damage yet.

The Sensei motor is attached to a U-Shaped heavy metal plate molded into the fuselage sides at the nose. In these pictures I have removed the actual motor mount that attaches to the U plate, and gently pushed the motor back out of the way.

[Billyboy46]

I had carefully picked up all the pieces of foam so I was able to jigsaw puzzle the pieces together before gluing anything.

I used foam-friendly CA for all this repair (The Sensei is EPO) wit accelerator as required.

[sihinch]

Welcome to the forum! Great post and congratulations. Thanks for sharing it.

[Billyboy46]

I reassembled the motor with mount etc. and checked to see if the motor still worked, didn't vibrate etc.  and I was lucky! It all worked like new.  Also of note, one blade broke off the prop but the spinner was hardly scratched.

The model did a bit of a cartwheel on it's way through the weeds and dirt but fortunately the only damage was a bit of foam-rash on the wing-tip leading edges and a slight weakening of an elevator "hinge". All CA'd back into shape.

I was concerned about the strength of the nose with all the joins behind and around the U-shaped plate, so I applied a fibreglass bandage soaked with CA to reinforce it. (picture k).

I was going to buy a fresh cowl but Dave at Pinnacle told me they're not available until late Sept or Oct - he made the suggestion to try and make it symmetrical - so I did - picture j.

The cowl is held in place with white electrical tape - easy to remove.

New prop installed, plane assembled and checked out ready for test flight. Interesting fact - I had to rebind the transmitter and receiver to get the motor shut-off to work correctly. Motto - check everything.

[Billyboy46]

Thanks for the welcome Sihinch - hopefully the last chapter here.

After the checkout flight with my instructor we determined that it was too difficult to trim and that it was too nose heavy. When you balance the plane on your fingers as suggested in the manual it is very difficult to get a true reflection of how level (or not) the model is. So I built a jig that I could balance the model - few pieces of wood with two dowels as "fingers".

The model was definitely "nose down" as repaired - probably all the fibreglass and CA added to the nose. (picture p).

I kept adding steel washers to a flat spot on the fuselage roughly equidistant from the main spar as the nose. (pictures q and r).

The four washers that balanced the model I figured would be the weight I needed to remove from the cowl. (The Sensei comes with five (I think) steel weights in the cowl) I removed one weight and it was about equal to the weight of three of my four steel washers - I figured that was close enough - see picture s.

Next step is the recheck flight - but Saturday is looking like rain.

[sihinch]

Let's pray to the RC weather gods!