HerbK

Yes I move the pack foward around a half of an inch for the power unlimited packs with the CF props. Doesn't change much more then that. I use Thunder 5400 packs as well which are around 1100 grams. They would be toward the front of the tray shown previously.

Herb

Bubblehead575

I got my first flights in yesterday with the CG 1/2 inch behind the wing tube C/L and the batteries centered on the forward edge of the landing gear block. I am using several battery types, Turnigy Compacts 5000, Power Unlimited 5100, and Dinogy 5000, with weights between 1180 and 1340. My total weight with the 1180 batteries is 3740 and I am using Futaba BLS 175 for Rudder and Elevator. I fly at the same field with Dan and we are up at 5300 feet and my wing Incidence is at 3.7 degrees Positive from the motor thrust. I needed only a little Rudder to Elevator mix to get the knife edge to track, and a little Throttle to Elevator to fix a pull to canopy on the down line.

HerbK

Bill,
Sounds like you and Dan now have the setup solved for your altitude. Like to hear your thoughts once you get a chance to run through the pattern a few times.
Herb

ltc

My Feedback: (3)

Here is a link to the information regarding the first 30 planes...

http://rcone.kr/board/index.html?id=bjair1&no=134

Lots of pictures and details...

grotow

Bill,
Could you clarify something? In all the information I have seen BJ put out(e.g. link mentioned in post #104) he states that once rear anti-rotation adjusters are moved to correct location there will be a total of 3deg of adjustment from -1.5 to +1.5. In order to achieve +3.7deg did you install adjusters outside recommended location?
Gary

Bubblehead575

Gary.
What BJ has said is that the first 30 kits came with a negative 1 degree and it should have had a positive .5 degrees. If you are using the nose-ring as your thrust line and also as your base line (I would highly recommend you do that). That would mean as compared to the motor thrust, the wings were at positive 1 degree. BJ wants you to move the aft anti rotation pin (wing adjustor) down 4.4 mm to increase the wing incidence to a positive 2.5 degrees from the motor thrust line. (I am at High Altitude and had to increase the amount of positive incidence to 3.7 degrees.) You should then increase incidence as needed to take out the pull to canopy on knife edge. If you are pulling to the wheels then reduce the positive incidence.

Hope this helps explain it better.

grotow

Bill,
Thanks for taking time to reply. Gary

pippy

I am at the build stage where I need to decide on my CG location. BJ I his blog says to set the CG at 260 mm from the canopy edge(I'm assuming rear of the canopy) but from this thread most of ye have set the CG at between 290/300mm which is at the middle to rear of the wing tube. How did ye arrive at this location? Is 260 mm too far back for stability?

Bubblehead575

Paul

I have a Nuance and several of the other guys in the area have Nuances and other BJ planes, Prolog, Episode, Bi-sides. Most of us tend to prefer a more nose heavy CG then BJ recommends (about 15 mm further forward) Close to the aft side of the wing tube. If you read some of the threads for the other planes, most of them recommend a more forward CG.. BJ recommends 260 mm (from the aft canopy edge) for the Nuance, I fly it at 277.

My CG on the Inspire is at 288 from the aft canopy edge, but I may move it further aft, I think it may let me take some of the extra positive incidence out of the wing, and let me have a lighter touch on the elevator inverted. But the weather here is not conducive to flying right now, and I only have 1 day of 7 flights on the Inspire. I am going to get some more trim flights in, then I will see where I land. Right now it looks like a little Rudder to Elevator mix and my knife edges are close.

HerbK

Paul
if you look at the picture in post 41 that shows where BJ set the CG on the prototype. I was flying with the CG just forward of that but now I am pretty much on that spot. I like the rudder needed in knife edge and the elevator inverted. The plane locks in well with this CG. I'm not sure what the benefits would be further back except at altitude like Dan and Bill.

Herb

pippy

Thanks guys, I will start with the CG on the wing tube and go from there.

grotow

At some point I will be installing Gator 8mm front wing adjusters. Is the adjuster installed with just the screws or is something like JB Weld needed in addition? Gary

Bubblehead575

The Gator uses 2 machine screws

mups53

My Feedback: (41)

https://www.youtube.com/watch?v=--L_1Hlnmls
Herb's newest video. Now I can learn the new masters pattern a lot easier. Thanks Herb and tell Mitch that his camera skills are getting really good. Is your field next to a Moto-Cross course?
We have a large shipment of the new Inspires arriving next week.
The issue with the improper incidence has been fixed on anything new shipping now.
From BJ and myself we are very sorry for this issue ever having happened.
Thanks, Mike Mueller

HerbK

Mike,
That's the sound of the Contra hard at work. Actually there is a Motocross track next store and the wind was blowing the sound toward us.
I am working on a new Inspire and with the corrections BJ has on his blog the incidence matches my prototype.Not that big a deal and glad we found it early on.

Herb

pippy

Hi all, my Inspire is ready to go. It was probably the easiest build I have done in years. The firewall set up and the all moving tail made the set up very easy. My final weight is 4880grms ( with a battery of 1180). This is with extra support around the undercarriage area ,extension pieces on the undercarriage ( soft runway) and larger wheels than normal ( again soft runway). I am happy with that weight.
I have put the wing adjusters on the rear carbon rod and I also put a plastic bolt and wing nut on the front of the wing. I don't like the front supports to be floating.
Unfortunately it could be while before the weather and flying site are good enough to fly it so I must be patient. I will report here when it does happen.

underdw

My Feedback: (2)

We got some incredibly warm and calm days this week, so I was able to get back to trimming the Inspire: Here are some updates/conclusions. Keep in mind that I am at high altitude (5400ft), so your results may vary. It's flying very nicely now!
-A little differential helped the rolls to be more axial.
-Multi point mix curves for Rud-Elev and Rud-Ail are the way to go.
-Spins require keeping the props spinning going into the break. Without the motor on, a wing tip would drop prematurely.

Dan

pippy

Dan, when I had that problem of tip stalling on my episode, wing fences stopped it. I do also have the props running on stalls.

underdw

My Feedback: (2)

Yes Paul, I remember you saying that. I tried a couple of iterations of wing fences on my Contra-Episode, but finally concluded they didn't help (my setup, altitude, etc). I need to continue to work on that. I think I neglected to post my pics and conclusions on the Episode thread.

I think perhaps the Inspire is less prone to tip stalls due to its' double taper wing as opposed to the Episode's triple-taper. I can land the Inspire with a slower speed and higher AOA too. The snaps are very nice with both planes.

HerbK

Just received my second Inspire from F3A. I had Dave Snow do some of the set up work as I am trying a different motor for the Contra and wanted Dave to do the install. We measured the wing incidence after making the correction BJ shows on his site and after making the corrections it matches up with my prototype within a tenth of a degree or so. I will fine tune if necessary once i fly the plane.
I do not have a tip stall problem and try to enter spins with the motor off completely. I do have the motor running in stalls. I have no differential on the ailerons and rolls are axial. I think that shows in the video on the upline rolls in the stall turn.

pippy

Dan,glad to hear it doesn't tip stall easily and can land slower as my flying site is small. Accuracy on landing is vital.

pippy

hi bill, if the model is pulling to canopy on knife edge surely you need to decrease the incidence to correct it and vice versa. I am assuming positive incidence is moving the front of the wing up.

Bubblehead575

Paul

Not sure of the actual aerodynamics and why it works the way it does. I am speculating here and someone with more knowledgeable then me can correct me. And I am assuming it is the only thing causing the pull.

But I think the pull to canopy is a result of elevator trim. The incidence and balance causes the elevator to be trimmed with up elevator to keep the plane in level flight, and when you go to knife edge, the wings has less effect and the elevator has greater effect, thus a pull to canopy.

To correct: You increase incidence which requires less up elevator to maintain level flight and when you go to knife edge it no longer pulls to canopy.

Now you also have to deal with the impact of the incidence has on how your CG feels. You may want to move the CG as well.

pippy

Thanks bill for the reply. It sounds like it makes sense the way you put it. It is going to take a bit of work to get th balance right especially getting my head around the all moving tail. I found it extremely sensitive so I will have to put in some exponential to soften it. I will experiment with CG also.
All in all it felt quite good for its first outing. Snap was good,stall into spins was good and best of all landing was easier than the episode. No trim required on ailerons or rudder.

mups53

My Feedback: (41)

We just took delivery of the newest shipment of Inspires. All of these have a incidence set correctly. Yipeeeeeee. Mike