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BJ Craft Passion

Old 12-07-2014, 07:07 AM
  #26  
flyintexan
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With the rudder tray mounted up I moved on to mounting the Neu motor and esc. I must thank my good friend Richard for his help in figuring out the best way to get the job done. The kit included two round discs that appear to fit back to back and are marked with a centerline offset for thrust. We decided to cut and fit the front facing disc roughly to handle the budd mount. We glued the two discs together and drilled a hole through the blank disc (centered) for the Neu prop shaft. We put the shaft and prop washer through and used an old spinner backplate to draw it up snug inside the nose. This was not going to necessarily keep the front firewall parallel to the nose so we assembled a set of ply washers to go between the back of the spinner backplate and the firewall face. The height of the stack of washers was just enough to let the firewall touch the inside of the nose but not wedge. This took plenty of sanding on the laminated discs to get the fit just right. The spinner backplate/shaft/firewall was taped to the nose so I would not move and from the rear of the firewall I applied hysol epoxy around the firewall disc. I let it cure and the next morning applied another small bead of hysol, this time around the front edge of the firewall. The rear disc was then dremeled out to match the front facing disc. I still needed 3/8" thick spacers to get the Neu to the right distance from the nose face....clear as mud right?.. Anyway, I'm quite happy with the final results. With the motor front mounted I fitted the rear supports and glued those in. BTW, the screws in the front pic were temporary...didn't have the 6-32 SHCS in the length I needed.

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Old 12-07-2014, 07:21 AM
  #27  
flyintexan
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Time for the battery tray. The laser parts included in the make a simple tray. I fitted the crossbraces to inside width of the fuse right behind the motor. I added some hard balsa triangle stock and tack glued the tray inside the fuse. I set the tray height basically even with the height of the motor. I secured the tray and support donuts with Hysol. The HV80 esc was mounted on a hard balsa and lite ply plate below the motor right behind the nose air inlets. I added a hard balsa plate across the back of the battery access area and mounted a Rx battery here. This may change but I really wanted access to it for the first flights. In the end I needed to fill the lightening holes in the battery tray to allow me to use full length Velcro strips on the tray..just my preference. I cut and fitted some hard balsa in these holes and used a little sanding block to get the surface smooth and flush. Everything is a rather tight fit so hopefully the CG will not need serious adjustment. I briefly picked up the loaded fuselage and thankfully the balance point is about a third back on the bottom wing saddle. That should be close enough to adjust with minimal equipment movement and/or added weight. As you can in the last pic, I added the included stab fences with some silicone glue. The included fence fixture worked very nicely. The kit includes a clear canopy that can be fitted as seen in another thread here on rcu. I'm not sure what I want to do exactly with the canopy so I used silicone glue to secure the stock fiberglass one for now until I decide later.


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Last edited by flyintexan; 12-07-2014 at 07:31 AM.
Old 12-07-2014, 07:29 AM
  #28  
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I mounted the Rx under the rudder tray and set up the radio stuff. With a falcon prop and no batteries the assemble plane weighs in at 3726g. I have 1150g batteries as well as 1200g (5100mah) batteries to use. Very good in my opinion.

If the weather breaks later today I hope to give it a go. I'll get some assembled pics in good light as well.

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Old 12-07-2014, 07:40 AM
  #29  
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a friend of mine in Korea, newly got a BJ CRAFT PASSION this month and did a successful maiden flight.
Maybe he is the first flyer for PASSION in Korea, he said a great plane. He just did a maiden flight with some maneuvers only. so I couldn't get details report
but, he said the general performance is better then his previous Axiom. I post some pictures here.
The transparent canopy comes with the plane together but had to cut out and add some his additional job.

Elec. motor: Hacker Q80 14XS, The other one is OS motor
ESC: Master spin pro 95A
Transmiter: Futaba 18MZ both
Weight: 4,880g with battery (battery only 1,260g)
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Old 12-07-2014, 02:10 PM
  #30  
flyintexan
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Despite the overcast weather, I got 4 flights on the new Passion today. I must say I'm quite impressed. I had a 21x13.5 falcon on hand so that is what I tested with and this plane is surprisingly fast...but this prop may be a touch more pitch than is needed. The CG is very close as the plane shows a very slight pull tendency in downlines. 1% down with idle took care of that. A 45° power-on upline, rolled to inverted and the plane nearly held the line without dropping the nose. Again, I think the CG is very close and could perhaps go back very slightly..I will get a few more flights before trying a change. The motor could use a pinch more right thrust..but only a pinch. Snaps are excellent, spin entry and rotation seems just fine, stall turns are very controllable. KE there is zero roll couple and I mean dead zero. There is a very slight pitch to the canopy in both directions, but again, I'm wondering if moving the CG back very slightly will take care of that. I mixed only about 6% down with full rudder (nowhere near the KE rudder input and cruise speed) and it seemed to take care of it for the short term.

I'm impressed with the rudder power, roll stability throughout a KE loop and the energy with which the airframe carries out from a downline. Perhaps the frontal area (as it appears) is quite small and the drag and yaw/pitch stability created by the large tail/aft area contributes to how good this plane feels. I noted a similar aspect in Bryan Hebert's Allure. Akiba has hit a nice compromise on yaw/KE sportiness and straight line stability. Time will tell as more flights, fine tuning, and flights in front of my peers will allow me to report further. Surprising to me, several non-pattern guys at the field were excited about the looks of the airplane.

For having only 4 flights, I'm very pleased that I am only able to nit-pick at the little things listed above. Based on post flight voltage, my battery usage looks to be about 2900-3000 mah for the "P" pattern. In front of judges and at a little more distance I would expect more but not more than 3300mah. Again, time will tell. Maybe next time out I'll put it through some "F" patterns .

Many thanks to Mike of F3AU for letting me get my hands on one of the first ones.

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Old 12-08-2014, 09:02 AM
  #31  
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Holystone,

Very nice cockpit and pilot!

What size propeller are you guys using?

What servo are you using on the flying stab?
Old 12-08-2014, 09:36 AM
  #32  
mups53
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Mark it looks very cool.
Not bad for less than a week to build it and get it into the air. Now it's time to have fun.
I like the clear canopy too. It looks very sophisticated. Mike
Old 12-09-2014, 06:34 AM
  #33  
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Hello
I asked them today, they said,
The Prop. Q80 one used Falcon 20.5-14.5 and The OS one used 21.5 - 14.5
Elevator servo, Q80 one used JR NP91MK2, The OS one used Futaba 9071SD.
I hope it's helpful to you.

Sungho
Old 12-09-2014, 06:59 PM
  #34  
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Sungho,

Thank you for the info. I'm anxious to get out and fly again soon. I have adjusted some things and got the main battery moved back slightly.

Right now my CG is about 98mm back from the LE at the center (root rib) of the top wing.


-mark
Old 12-10-2014, 07:43 AM
  #35  
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Hi Mark

BJ asked me to say thank to you about good report about the Passion.
BJ Park wants give you some tips about how to properly set up the KE and down line pull.
He said, just giving more positive incidence of main lower wing with roughly 2mm spacer,it can kill the pull tendency at KE. and might be mitigate at the down line depend on your power source. .

The background is, this plane has higher HTVC(horizontal tail volume coefficient) and full flying stab. So when the gravity direction is changed like KE or downline, the pull tendency comes out much more from the full flying stab, less from the main wing incidence. So, in order to kill the pull tendency correctly you have to get more main wing incidence.
.
So, Long story short.
(1) Gaining more positive main lower wing incidence, lead the plane left up at level flight.
(2) the full flying stab trim should move to the positive incidence to make the straight flight.
(3) Gained positive incidence of the stab will reduce the pull tendency at KE and down line both. Adjust the incidence with adding up or losing it until get the straight flight without program mixing.

But, please be careful, this correction makes sense only for Passion which has higher HTVC and full flying stab. For other planes may not be correct. So this guide can not be generalized for all F3A pattern flying models. BJ always advise me that there must be consideration of the conditions on that plane first, before we talk about any conclusion…… in order words, before we choose one action for correction, we must consider the planes basic specification and condition. Otherwise it leads the wrong result.
The above correction is the best example……

In your maiden flight with your current CG, the above guidance is verified under the condition of increased main win incidence, strong HTVC which can surpass the main wing twist moment, Full flying stab., long nose moment. Good luck thanks.

Sungho

Last edited by Holystone; 12-10-2014 at 08:04 AM.
Old 12-10-2014, 08:00 AM
  #36  
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Mark

Speaking of the CG,

Akiba san's CG is exactly 113mm from lower wing leading edge.
BJ 's favorite CG is 120mm, cause he likes to fly closer and slowly.
The above two Korean guys CG are 110mm, and 115mm. just take these CG for your information only.
You can move your battery to the backward all the way.. so that you can feel how the performance is changing at each points.

BJ said, Passion has strong HTVC so, if you move your battery to backward, the elevator trim won't be change that much.
Have a nice flying with Passion.

Sungho

Last edited by Holystone; 12-10-2014 at 08:06 AM.
Old 12-10-2014, 11:59 AM
  #37  
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Sungho,

Thank you again for sharing such good information. I will first move my CG back and flight test. The amount of "pull" in downlines and KE is very little and the snaps and stall turns are very nice.

I flew the airplane through the "F" pattern for the first time today and I was very pleased. I still have to work out some fine adjustments to the radio (AFR/EXPO, etc.) but the trimming process is progressing nicely.

If the trimming process keeps progressing this well I may have to consider a sister plane in a custom scheme... One to match my monoplane would be nice.





Regards,
Mark
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Old 12-11-2014, 11:42 AM
  #38  
mups53
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Thanks Sungho for sharing BJ's thoughts on the plane. We have more coming very soon. With Yellow Scheme this time.
I think I may have to keep one for myself.
Mark I love the picture of you with the winning trophy for 1st place at the Nationals. The hat looks nice too!!
Mike
Old 12-11-2014, 05:01 PM
  #39  
flyintexan
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In regards to CG, I setup the plane carefully and accurately measured back from the LE of the bottom wing and my original setting is actually about 108mm back. I added tail weight until I reached 120mm which required 28g added next to the tailwheel. I flew it this way and noticed no real change to the slight pull in KE. I prefer the feel of the airplane with a more forward CG. I have now moved the CG forward to Akiba san's position of 113mm and I have added a 1/16" (1.5mm) shim to the rear of the bottom wing. I will try this as soon as I get time to fly again.
Old 12-11-2014, 05:43 PM
  #40  
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Mark
Yes, that's what BJ said, strong HTVC and full moving stab effect. this plane has more influence from the tails so, with moving CG is not much helpful to change the KE
I'm also look forward to hear from you how it's changed after adding 1.5mm spacer for main lower wing. Have a nice flying.

Sungho
Old 12-14-2014, 05:07 PM
  #41  
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Sungho,

I got a few more fights on the plane and now some flights in windy conditions. I really like the forward cg position. I think the shim helped, but not as much as I thought it would. I still have nearly the same amount of down elevator mix with rudder, but again it is very little and the plane is very solid in the F pattern. I added a pinch of right thrust and that was just right. Snaps are still just amazing. In 15+mph wind I was able to fly better than expected. The wind causes the plane to jump around a little bit but I was able to hold lines just fine. I'm not sure if I should try a shim on the top wing as well or fly it a bit more as is first...it's really close to competition trim at only 20 flights.

In addition I found a way to smooth the higher speed downline exits by mixing a small amount of flaps/spoilers to elevator input. The Ailerons drop about 4mm with full up elevator and raise up the same with full down. I think the extra drag induced by the Ailerons while using elevator settles the airplane very nicely. This mix is not engaged when my snap rate switch is on. It also helped slow down the airspeed right at landing/flare out.

-mark

Last edited by flyintexan; 12-14-2014 at 05:10 PM.
Old 12-15-2014, 05:45 AM
  #42  
Holystone
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Mark

It sounds like you are getting close to competition trim. yes, maybe it will help to reduce the pull to canopy with another shim to the upper wing. but if it's not
serious and can adjust with program mixing then just leave it. it's good for you. you get better way to smooth the higher speed downline exits by mixing.
That's the real fun and self confidence for your flight and plane. I envy you that you can still have a nice flying at your place. In korea it's already winter.
I look forward to hearing from you more fun and better performance with your PASSION.

Sungho
Old 12-22-2014, 07:56 AM
  #43  
flyintexan
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Sungho,

I am now up to about 35 flights and have continued to tune the throws and such. I'm really enjoying flying the plane. We finally got some sunshine and blue sky the other day and the pink shows up very well in the sky. I took out a bit more of the elevator throw by moving the clevis inward on the elevator servo arm. I feel much better about the radio setup and CG. I have left the CG at about 113mm. A couple of people have flown it of various skill levels and an encouraging remark from an Advanced pilot was that the airplane felt very easy to fly and solid in straight lines. I have managed to fly the airplane through the "P" pattern at a slower pace and closer (150m). During this experiment I tried some very slow uplines and airplane wants to begin to pull to the wheels. A slight increase in upline velocity and this went away..apparently a thrust element is overcoming an aerodynamic element. I am not skilled enough to fly the "F" slow and close..

My typical battery usage (170m) is now at 3000-3200mah.

The plane still impresses me with its lower than expected drag. This is not a bad thing, just unexpected, as a result this plane is much better than expected in the wind. A good friend pointed out that the flying stab is likely to have much less drag than a traditional stab/elevator setup. I see that in some pictures of the Passion kit planes there was a thick rudder trailing edge? Was this only on the prototypes? Was it used together with any stab fences or as a substitute for the stab fences? Did Akiba try a thicker trailing edge on the flying stab?

Have you guys considered trying an SDC 3 blade (20x13)?



Best Regards,
Mark
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Old 01-09-2015, 05:48 PM
  #44  
flyintexan
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Goofin around...

https://www.youtube.com/watch?v=k5W3O1gqaiU
Old 01-10-2015, 07:51 AM
  #45  
mups53
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Hey Mark I love the video.
The snap looks incredible. I also like the way it presents in the air.
I've just listed the Yellow Scheme ones.
I have a small amount on the ship right now. Due in a few weeks.
http://www.f3aunlimited.com/bj-craft...-yellow-scheme
Thanks, Mike Mueller
Old 01-10-2015, 01:58 PM
  #46  
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Mark,

Can you tell me how many degrees right/down thrust you wound up with.

From the interior picture showing the back end of the motor, it looks like there was considerable right thrust built into the nose ring.


Thanks, J e r
Old 01-10-2015, 02:08 PM
  #47  
flyintexan
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Jer,

yes, there is a good amount of right thrust in the nose. I actually ended up adding a touch more as well. I also have a 1.5mm shim under the te of the bottom wing and under the le of the top wing. The shims seem to be common among passion owners in the far East. My cg is about 115mm back from le on the bottom wing. I'm not sure the shims would be needed if running a more aft cg. I am really pleased with how it tracks and Flys.

good luck,
Mark
Old 01-22-2015, 07:56 AM
  #48  
mups53
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Guys the Yellow Passions are scheduled to start shipping to customers next week.
I have a small amount available.
Mike Mueller
Old 02-16-2015, 09:29 AM
  #49  
flyintexan
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I have put a Falcon 3 blade 19.5x13 on my Passion and it seems to have slowed the downlines a bit, a very nice improvement. As of yet I do not see any increase in mah usage. Power delivery as expected, is more manageable yet it still has the punch for the opposite snaps in F15.

I am still playing around with CG and as I noted before the airplane will show a slight pull to the gear when trying to go slow in an upline. I tried a thrust adjustment to no avail so I suspected a vertical CG issue. A quick glance at the side of the Passion and you can see the thrustline is quite high resulting in a vertical CG that is below this thrust line. I added tailweight to the very top of the vertical fin (1-1/2 oz) and sure enough, the pull was greatly reduced. As I get more time I will experiment a bit more before reporting my final favorite CG position/measurement. In the meantime, the Passion shows excellent promise for the F maneuvers. I removed the little bit of up elevator mix with rudder that I had programmed so that the plane would be more pure in rolling/looping elements. Very happy with that.



Regards,
Mark
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Old 02-17-2015, 04:33 AM
  #50  
mups53
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Hey Mark that's a remarkable discovery. Something I wouldn't have ever considered. The first time I ever came across vertical cg was on foamies. There the position of the lipo is very critical.
Thanks for sharing this discovery.
Mike

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