R90 Construction

[vandelescrow]

I'm in the process of buiding a Raptor 90 3D and have a few questions.

1) I greased the autorotation gear before putting the gears into the frame. Spinning the main shaft feels fine but when I hold the white (upper) gear as if in an auto it has quite a bit of drag. Will this loosen up after a few flights or is something not right?

2) When assembling the tail boom the directions say to put some Zap glue around the outside of the tail drive bearing housing before inserting into the tail boom. How do you keep the glue in place while sliding it down the boom?

3) I have not greased the bearings in the blade grips yet (just test fitting stuff) and while rotating the blade grips they feel notchy. I tried putting shims between the washer and bearing to see how it would feel as suggested in the manual. I notice if I use 2 or 3 shims the blade grips will not rotate. How many shims have you guys found to be best and will the notchy feel go away? I have 1 shim in there now.

[Ah Clem]

Hello Vandelescrow,

I just built one of these too!

"1) I greased the autorotation gear before putting the gears into the frame. Spinning the main shaft feels fine but when I hold the white (upper) gear as if in an auto it has quite a bit of drag. Will this loosen up after a few flights or is something not right?"

I used triflow on mine, after working with ramp roller clutches years ago in Heliboys. Some people use transmission fluid. I general, I don't think you want anything heavy or sticky here. Hopefully others will chime in. In answer to your question, yes it should free up from use.

"2) When assembling the tail boom the directions say to put some Zap glue around the outside of the tail drive bearing housing before inserting into the tail boom. How do you keep the glue in place while sliding it down the boom?"

The Zap is to hold the bearings in place on the drive shaft. The should be spaced equally, per the instructions. After it dries, then the whole assembly is installed in the boom. I think I used "Goop" on the outside of the plastic bearing holders, the slide the whole thing into the boom.


"3) I have not greased the bearings in the blade grips yet (just test fitting stuff) and while rotating the blade grips they feel notchy. I tried putting shims between the washer and bearing to see how it would feel as suggested in the manual. I notice if I use 2 or 3 shims the blade grips will not rotate. How many shims have you guys found to be best and will the notchy feel go away? I have 1 shim in there now."

The bearings should not feel notchy. I believe I installed two washer. Make sure that there is no grit or other foreign substance in the bearings.


The assembly of this machine went very well. The parts all fit and the instructions are very good. The only part I did not like, was the installation of the three 8717's discussed on the other thread.

Mine should fly for the first time later this week.


Good luck to you sir!

[BT Bones]

I just finished my 903D last week.

Question 1:

Mine is smooth and free. Did you get any loctite on the shaft? The assembly is straight forward on this step. Is any part worped?


Question 2:

I did not use ZAP during this step. I measured the placement with a long control rod and marked the rod with perment marker. I also noted the drive shaft distance "amount sticking out of tailboom when it was installed. I then used goop on the outside as stated in the directions. Next I used a 30 size tail boom to push the tail drive bearing housing into position. This took about 5 minutes to complete with the help of a buddy.

Question 3:

I followed the direction to the tee. Once I tightened the everything down - "smooth". Read the important note at the bottom of page 24. If you add more shims - know what your helicopter will do.

I hope this helps.

[vandelescrow]

Thanks guys. I got the main blade grips to move nice and smooth (no shims and bearings greased, also I think I may have had the thrust bearing backwords on the test fit). The tail boom I got asembled, it was a pain to get the outer edge of the bearings over the lip of the boom. I used CA to glue the bearing to the shaft and let it cure over night, then got the first bearing started, put zap around the edge and slid it in. Trying to get the second one in the CA broke loose. When I did the initial assembly I noted the space from center to center of the bearings and from the bolt hole on the shaft was 12 1/4 to be centered. Because I had zap on the first one I had to be quick and was only able to get the second one (using a spare threaded rod) apx 10 inches. Glueing the bearings to the shaft I hope was to help get the bearings in the right space? and wont cause a problem because it broke loose on the one?

I almost have it fully assembled and I have a part I can not find in the manual where it goes. It looks like a spacer 4mm thick one side is 5mm in diamater the other is 6 1/2mm and this side has a lip on it. Anyone know where this goes?

Thanks

[Ah Clem]

Vandelesrow,

"Glueing the bearings to the shaft I hope was to help get the bearings in the right space? and wont cause a problem because it broke loose on the one?"

I assume that gluing the bearings to the shaft is for two purposes:


1) To locate them on the shaft during assembly.

2) To prevent the shaft from turning inside of the bearing, which could result in shaft wear/failure or "whipping" of the shaft.

In retrospect, I wish I had used JB Weld to attach the bearings to the shaft.


Regarding that spacer piece that you mentioned-I too have that left over, as well as the tail pushrod parts for mounting the servo up front (although no space to mount it up front due to the collective push-pull bellcrand mount).

I would like to know what that part is for as well.

Unfortunately, I am so busy today I cannot take mine out an try it. I am swamped and it is agravating to have a brand new machine just sitting there, ready to go.

Please keep us posted on your progress. We can compare notes.


Thank you.

[Ah Clem]

Update!

I finally got the Raptor 903D in the air, although it was only a brief hover in the back yard (and yes, it is way to big for the back yard).

It was running very rich (four cycling). My first impressions are that it feels big, easy, and very, very stable. It did not feel especially quick, but I assume that was due to the low RPM on the head (again, running very rich for first run).

The tail rotor is quite powerful, by the way.

I am off to buy another starter now. I know that my Thunder Tiger starter will die an early death (at least, that is what I have been told) if I try to start the .91 with it, and my 25 year old Sullivan 24 volt starters (one of which I just used) are in very bad shape.

[vandelescrow]

I use the hydratork starter from heliproz on my 50, should be enough for the 90. Here is a link for it http://www.heliproz.com/prodinfo.asp?number=804577

Glad to hear you got it in the air. It will still be a while for me. still need a few more parts / pay checks befor it is finished.

[Ah Clem]

Vandlescrow,

I went with the big Sullivan starter and will be running it on 24 volts. My old Sullivan 24 volt starters would work, but the swtiches were bad (could not shut the starter off consistently due to the rubber being rotted and the switches being old and burned).

I am trying to get out this morning, but seem to be having no luck.

I need to get a half dozen tanks or so through the motor.

[Ah Clem]

I got five or six tanks through the Raptor 903D today, each flight tweaking the needle valves on the pumped OS .91. On the last flight, I flipped it to "Idle Up II" (governor on and set for 1950 RPM) and flew it around a bit.

Even though it is still running rich, there is a lot of power. It is extremely easy to fly, which I had expected and hoped for, but you never know until you actually try it.

The rolls are very flat and accurate, and the stability is excellent. It goes right where you point it. There was a bit of trim shift inverted (it tended to want to creep forward a bit when inverted) so I will need to check my balance.

The Sullivan Dynatron cranked the motor over on 24 volts with no problem.

I will probably not be able to try it again until next week.

[vandelescrow]

Ah Clem,

Did you set yours up for agressive 3D or standard? I'm building mine with the agressive settings.

[Ah Clem]

I set up everything on the most aggressive settings (flybar control arms, mixing lever position on the see-saw, etc.).

It is nowhere near as fast as the Knight 3D, but has a very nice feel to it.

Again, very easy to fly.

[Kinger]

Ah CLem - What paddles are you using?

[Ah Clem]

Kinger,

The stock blue paddles that came with it.

The size of the thing is intimidating, the flight characteristics are not.

It is amazingly easy to fly. It moves very quickly for its size. It is very precise also. And it is very, very smooooooth!


I am looking forward to flying it more.