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-   -   "Inspire" - Contra Powered Design - BJ Craft (https://www.rcuniverse.com/forum/electric-pattern-aircraft-385/11601510-inspire-contra-powered-design-bj-craft.html)

Bubblehead575 12-04-2014 11:19 AM

6 Attachment(s)

Originally Posted by serious power (Post 11930757)
Hi,
A case of 'Spot the difference' ??.
Looks like different wings, fuz,, ,stab and fin/rudder group in these pic's.
What is shipped ; The wing from 1 and the rest from 2 ?

Brian


I received mine from Mike this week, Here are some pictures to show what is actually shipping for the Contra version

http://www.rcuniverse.com/forum/atta...mentid=2052185 http://www.rcuniverse.com/forum/atta...mentid=2052186http://www.rcuniverse.com/forum/atta...mentid=2052187http://www.rcuniverse.com/forum/atta...mentid=2052188http://www.rcuniverse.com/forum/atta...mentid=2052189http://www.rcuniverse.com/forum/atta...mentid=2052190

Bill

pippy 12-04-2014 11:37 AM

Hi Bill, looks really nice. That's the one I hope to get. Did you purchase the firewall/ motor mount assembly for the contra? It looks like it would be such an easy install with it.

Bubblehead575 12-04-2014 11:51 AM

Yes,

Dan Underkofler and I are both going to try it but the shipping on it is lagging and Mike was not expecting to be able to ship it for another week or two. Since this is my first Contra I am leaning on Dan for a lot of help. especially since we fly at the same field.

mups53 12-04-2014 04:08 PM


Originally Posted by serious power (Post 11930757)
Hi,
A case of 'Spot the difference' ??.
Looks like different wings, fuz,, ,stab and fin/rudder group in these pic's.
What is shipped ; The wing from 1 and the rest from 2 ?

Brian

Brian point so noted. Your right. I took that pic on the right down. More news to come when I know more. It fooled me too.
Mike Mueller

serious power 12-04-2014 04:17 PM

Mike,
Ah ok !! - Thanks for the clarification.
It is a nice looking fuz,, .
Looks like the rear is a lot deeper and the cannaliser is mounted to the fuz,, (not the canopy).
We will watch this space so :)

Brian

underdw 12-04-2014 05:55 PM


Originally Posted by Bubblehead575 (Post 11931071)
Yes,

Dan Underkofler and I are both going to try it but the shipping on it is lagging and Mike was not expecting to be able to ship it for another week or two. Since this is my first Contra I am leaning on Dan for a lot of help. especially since we fly at the same field.

We'll fly 'em next weekend then Bill?
Dan

TonyF 12-05-2014 12:34 AM

I don't have details but I have been told that BJ Craft is working on a new model that can be built for glow. If you note in that picture there is also a chin cowl on that model. Not sure about the name. It's probably an early prototype in that pic.

Also, I have just received my Inspire and I will be doing an assembly thread as I put it together.

rm 12-05-2014 03:41 AM

That's good news to hear. I hope it happens.

pippy 12-05-2014 04:01 AM

Hi tony, look forward to your build thread.

mups53 12-05-2014 02:53 PM


Originally Posted by TonyF (Post 11931486)
I don't have details but I have been told that BJ Craft is working on a new model that can be built for glow. If you note in that picture there is also a chin cowl on that model. Not sure about the name. It's probably an early prototype in that pic.

Also, I have just received my Inspire and I will be doing an assembly thread as I put it together.

Hi Tony I look forward to the build thread.
I thought we ran out of stock yesterday but low and behold I found another Inspire at the warehouse. So one left till March or so when we will resupply.
It's very difficult to anticipate interest in a new design. This one has taken us by surprise.
We feel very privileged to be the North American rep for BJ Craft. BJ Park is a very nice person, fair and honest and the quality and value of his planes speak for themselves.
As his designs and company progress you can see an improvement in the quality. That is the mark of a good company. Not content to sit on their laurels striving to constantly improve.
It is their goal to produce the best flown by the best. Lofty but a great aspiration.
Take care and thanks for all the support my F3A friends have bestowed upon us.
Mike Mueller
F3AUnlimited.com

TonyF 12-05-2014 11:35 PM

Mike, I couldn't agree more. I've been extremely happy with all the BJ Craft models I have had and currently have. I hated to mid-air my original Episode as it was really flying well. But it had 850 flights on it so it had a good life. Looking forward to putting those kind of flights on the Inspire. on the 23rd I get the first cataract surgery. If my procedure goes as well as I have seen my friends have I may even be able to really see these models now!

mups53 12-06-2014 04:23 AM

Thanks Tony good luck with the eye surgery. By all accounts I have from friends it's likely to be a big improvement.
I'm lucky I feel I still have very good eyesite. I thought I was having issues a few years ago but with me it turned out to be Polaroid sunglasses and prescription sunglasses with curvature. That screws with astigmatism's. Now that I have all that squared away I feel like a kid again.
Mike

underdw 12-06-2014 06:42 AM

2 Attachment(s)
I've had a chance to do a bit of work on my Inspire.

I wanted to note that the rudder servo is more conventionally mounted than on previous BJ models. There are open bays for both the rudder and elevator servos - this speeds up the build.

Mounting the landing gear has always been tedious. You have to put the gear leg in place, insert screws, then position the clamping plate underneath the gear leg by feel and hope to get the screws engaged. This gets harder on the Inspire because the access holes through the gear bulkheads are smaller (a good structural improvement IMO). I'll share what I've done on 2 planes now: Installed the blind nuts directly into the gear legs.
-make a light counterbore/spot-face for the outer blind nut. I did it by hand with a dremel cutter. Just go deep enough to get a flat spot on the leg underside.
- drill out the mounting holes from the bottom of the gear to the diameter of the blind nut. Don't drill all the way through, just deep enough for the blind nut.
- Mark and drill 3, 1/16" holes for the spikes of each blind nut. Tricky, but they don't have to be too precise. See picture 1
-Install blind nuts and pull into place with a screw.
- Add a couple of drops of thick CA or epoxy to lock in place. Picture 2 shows completed leg.
-Now just insert the leg and tighten the screws.
-Disclaimer: these operations on the gear leg for the outer blind nut weaken the leg in the highest stress area. I haven't had an issue with my Episode and 100s of flights, but also haven't had any bad landings with it.
http://www.rcuniverse.com/forum/atta...mentid=2052623http://www.rcuniverse.com/forum/atta...mentid=2052624

grotow 12-09-2014 02:24 PM

When do you expect to start assembly thread?
Gary

underdw 12-11-2014 06:01 PM

4 Attachment(s)
A couple of "different" things on my Inspire:
- I decided to try the Gator adjusters that accept the 8mm tubes on BJCraft wings. They are slop-free, were easy to mount, and are lightweight. Only issue was a need to shim them so that they are parallel to the fuse centerline rather than the tapered sides. (this is true of the traditional Gator adjuster too) The picture shows them mounted, but I later added a piece of honeycomb across the fuse width that serves to make the sides more rigid in this area and also serves as a radio tray.

- I used the new Contra mount by BJCraft. It was well worth the $75. It saved a lot of time coming up with a firewall template. Best of all, the unit and motor can be pulled out the front of the plane. Thrust adjustments can easily be done by adding washers in the right location(s). A couple of pictures of the motor and mount are attached. Took me about 2 hours to install the motor!

I like the new hatch latch so far. Much more of a positive engagement than the Episode latch.

http://www.rcuniverse.com/forum/atta...mentid=2054210http://www.rcuniverse.com/forum/atta...mentid=2054211http://www.rcuniverse.com/forum/atta...mentid=2054212http://www.rcuniverse.com/forum/atta...mentid=2054213

underdw 12-11-2014 06:13 PM

3 Attachment(s)
All done! Entire build in 9 days- a record for me:) (and no, I don't have a job;))

I won't show interior pictures yet, since I'm leery of having to move the battery tray if I don't like the CG, so I haven't done a clean wiring job yet.

Mike forwarded me some photos from Herb that show CG, Elev throw, and Rudd throw. Herb commented that he preferred the CG a bit forward of BJ's mark shown.

Weather forecast for tomorrow is sunny, low 60s and dead calm:D!
Flight report tomorrow hopefully.

http://www.rcuniverse.com/forum/atta...mentid=2054215http://www.rcuniverse.com/forum/atta...mentid=2054216http://www.rcuniverse.com/forum/atta...mentid=2054217

HerbK 12-11-2014 07:54 PM

A couple of additional points for you to consider in your set up.
I did not show the aileron throws but the ailerons are pretty large so I only go to about 8 on that same throw meter in normal flight. Not sure which pattern you are flying but I set the throws based on the number and speed of rolls needed on the vertical lines which is 1 1/4 up in FAI P and Masters 2015.I did not need any differential for axial rolls.
As far as thrust on the Contra I am matched up to the nose obviously no right thrust and it has a touch of down thrust. Brenner has been using .5 degrees of down.
If you haven't flown contra's before you will need to maintain a little more airspeed on landing as the Contra is a great braking device when you go to low throttle.
You should not need any roll mix in KE and almost no elevator mix depending on your CG and exactly where the wing incidence is set on the production model. As mentioned in my previous post I added 1/2 degree of positive incidence to the wing. The flying stab automatically corrects for level flight and this corrects the elevator rudder mixing.
Look forward to hearing about your first flights. I would like to be out flying as well but all the rain in the middle of a drought is getting in the way.

pippy 12-12-2014 02:20 AM

Hi underdw, did the kit come with BJ wing adjusters but you decided to use the Gator ones instead. Or were there no wing adjusters included.

mups53 12-12-2014 06:15 AM

3 Attachment(s)
Here is a picture showing the CG location the normal elevator and normal rudder throws used by Herb.
He says you will need to setup condition switches to perform snaps, spins, and stall turns. Which is pretty normal.
I hope this helps. Sorry for the lack of info. This is due to it being a new plane on the market. Most of the building issues are covered in the BJ Craft Blog on builds for the Nuance. There are few differences.
Mikehttp://www.rcuniverse.com/forum/atta...mentid=2054378http://www.rcuniverse.com/forum/atta...mentid=2054379http://www.rcuniverse.com/forum/atta...mentid=2054380

underdw 12-12-2014 06:31 AM

Thanks for the additional comments Herb.
I'm right there with the aileron throw, matched the drive to the nose ring, and have the CG set at the wing tube bulkhead.
I fly Masters and FAI, though my F is pretty ugly:p

Pippy, the plane does come with the standard BJ adjusters: I just wanted to try the new Gator adjusters.

grotow 12-12-2014 03:52 PM

There are two carbon elevator tubes. Did you glue in just the forward tube or both? And if you glued both, did you then screw in both?
Thanks,
Gary

underdw 12-12-2014 05:35 PM


Originally Posted by grotow (Post 11936599)
There are two carbon elevator tubes. Did you glue in just the forward tube or both? And if you glued both, did you then screw in both?
Thanks,
Gary

I left the rear pivot tube "floating": no glue or screw.
On the front tube, I glued a piece of dowel in the open end, and screwed the tube into both stabs. Don't think this is the way it was intended, but it's what I did.

underdw 12-12-2014 06:00 PM

3 Attachment(s)
http://www.rcuniverse.com/forum/atta...mentid=2054473http://www.rcuniverse.com/forum/atta...mentid=2054474http://www.rcuniverse.com/forum/atta...mentid=2054475Maiden + 3 flights in perfect trimming conditions today! Everything went great!

My first reaction was: Wow, this plane is locked in! It's been awhile since I knew I was going to like a plane in the first minute of flight.
Visibility of the color scheme was good, even in the soft light of dusk.
Control throws were about right, but I will minimize the rudder throw as with the Episode and use a switch for stall turns.
Uplines were nearly straight.
Snaps were crisp and tracked well.
Need to check lateral balance, as a wing tip would slowly sag into a spin entry.

There were several indications that my starting CG (wing tube bulkhead) was too far forward. Foremost was a drastic pull to canopy on KE- even without rudder applied.
Over the course of the day, I moved the CG back over an inch for experimental purposes. The plane still flew well, but probably wasn't quite as locked in. KE pull to canopy lessened but still was strong.
Tomorrow I will follow Herb's advice and increase the incidence in the hopes of dealing with this.

Dan

HerbK 12-12-2014 06:36 PM

Both of the carbon tubes have hard points on the elevator for screws that go through the hard points into the carbon fiber tubes. I glued in the other half and used screws on the non glued side. I would suggest you secure both tubes as there is a lot of pressure and it will loosen up over many flights if you don't.
Herb

HerbK 12-12-2014 06:50 PM

Dan
That is pretty consistent with what I found. I think the change in the incidence should take care of most if not all of the down elevator mix. I don't think you will be as locked in if you move the CG back as the plane flies well as you saw with the CG over the wing tube.This is actually pretty far back already compared to the way some set the CG on BJ planes. You might want to check your T-Can to be sure it is perfectly level with the canopy support as this might cause the wing dipping going into spin's. I weighed both wing halves and they were within a gram of each other on mine. Glad you like the plane as always trimming is a process.
Herb


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