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Old Mar 10, 2010, 04:36 AM
72" of flying, flying, flying
Aussie_Toyman's Avatar
Sydney, Australia
Joined Nov 2006
2,089 Posts
I think I've found the problem.

It appears one of my 'unplanned' landings tore the horizontal foam in the fuselage just behind the ailerons.

I've glued a piece over the top of the tear and I'll report back after I get a chance to fly it.
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Old Mar 15, 2010, 12:43 AM
Look outside the Square
Boxhead's Avatar
Gosford, Australia
Joined Jan 2006
2,620 Posts
How did you go with the fix AT. Have you had time to fly it yet. Took mine out this morning and abused it . AND Thoughly enjoyed it . Even the Gala's following it had a Ball flying with it. Cant believe that more fella's arn't flying The Ultima. Its a Ball Tearer.

Have been looking for something small to fly at work in the Engine Bays when the Boy's Roll the Appliances ( trucks ) out to check them of a morning. HC have a couple of Micro Epp planes, the Yak and Piaget but havn't decided yet. Any Suggestions.

Bx
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Old Mar 15, 2010, 01:46 AM
EP 3D Flyer
feda's Avatar
Hamilton, Canada
Joined Nov 2005
1,029 Posts
Quote:
Originally Posted by Boxhead View Post
How did you go with the fix AT. Have you had time to fly it yet. Took mine out this morning and abused it . AND Thoughly enjoyed it . Even the Gala's following it had a Ball flying with it. Cant believe that more fella's arn't flying The Ultima. Its a Ball Tearer.

Have been looking for something small to fly at work in the Engine Bays when the Boy's Roll the Appliances ( trucks ) out to check them of a morning. HC have a couple of Micro Epp planes, the Yak and Piaget but havn't decided yet. Any Suggestions.

Bx
Piaget is a very different plane than Ultima BX. It is designed for flying patterns (e.g., F3P maneuvers) instead of tumbling.
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Old Mar 15, 2010, 04:51 AM
Look outside the Square
Boxhead's Avatar
Gosford, Australia
Joined Jan 2006
2,620 Posts
Thanks for the info Feda

Bx
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Old Apr 05, 2010, 04:49 AM
72" of flying, flying, flying
Aussie_Toyman's Avatar
Sydney, Australia
Joined Nov 2006
2,089 Posts
I finally got my Ultima to behave the way I expect it to .

I'm pretty sure most of the problems were caused by me crashing it into the ground a few too many times, but it's all nice now.

All up I moved the battery back to just in front of the separator, fixed the broken fuselage just near the ailerons, and cut the nose apart and added two 3ply triangles to strengthen the motor mount area as I was getting a lot of thrust angle changes in flight.

It flies really nice now, a whole lot more predictable .
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Old Apr 05, 2010, 04:53 AM
How many planes is too many?
groovejet's Avatar
Melbourne, Australia
Joined Aug 2007
3,855 Posts
Sounds good AT. I've occasionally partially split the foam of the motor mount away from the fuselage on various Hokusei kits after various hard nose-ins and, as you say, the motor thrust angle changes whenever you adjust the throttle. I usually squeeze some 3M Scotch 6225N in the split and that deals with it.
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Old Apr 22, 2010, 04:46 PM
How many planes is too many?
groovejet's Avatar
Melbourne, Australia
Joined Aug 2007
3,855 Posts
Speaking of 3M Scotch 6225n glue, I just found a great combo price on bestvaluerc. I'm used to paying a little more than $7 USD per tubes, but a combo purchase containing 2 tubes can be had for $11 USD.

http://www.bestvaluerc.com/shop/shopexd.asp?id=276

I'm going to put a big order in but I'll leave some tubes for you guys .
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Old Jun 16, 2010, 01:55 PM
Ride Blue
jholen's Avatar
United States, WA, Sammamish
Joined Aug 2006
1,495 Posts
Almost completed!

Just need to setup all my linkages and she'll be ready!

Included is a pic of my reinforced nose. Is this adequate enough GJ or should I add some more?
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Old Jun 16, 2010, 11:02 PM
How many planes is too many?
groovejet's Avatar
Melbourne, Australia
Joined Aug 2007
3,855 Posts
Looks good jholen. You're certainly getting your 3 kits built pretty quickly .

You've got tape in the right areas, but personally I would add another strip or 2 of tape vertically on the fuselage sides so the first inch or so of the nose is protected. Check some of my photos or videos to see where I have extra tape if you're not sure what I mean.
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Old Jun 21, 2010, 07:07 PM
Ride Blue
jholen's Avatar
United States, WA, Sammamish
Joined Aug 2006
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Quote:
Originally Posted by groovejet View Post
Looks good jholen. You're certainly getting your 3 kits built pretty quickly .

You've got tape in the right areas, but personally I would add another strip or 2 of tape vertically on the fuselage sides so the first inch or so of the nose is protected. Check some of my photos or videos to see where I have extra tape if you're not sure what I mean.
Took your suggestion on adding some more tape and glad I did. Here is a brief video of part of my maiden.

Unfortunately I don't think we captured what I really wanted to capture.. the plane flies great, nice and level at half throttle, but develops some weird characteristics when at WOT. The plane at times would go into this death spiral into the ground unless you let off WOT.

Watch the below video - I know you can't see it the first time, my wife is new at this recording thing, but after it climbs (I still have control) and I half loop to level flight it just banks right and dives - I'm at high rates and trying to pull out but can't. I'm sure I could have saved it if I had backed off throttle. Look at the 53 second mark to see the described behavior.

Hokusei Ultima BX Maiden (1 min 0 sec)

Think this was caused by the motor mount/thrust angle? I can't think of anything else being that it flew nice and level at half throttle, would knife very nicely, as well as do everything else. Just had issues at WOT.

Here's pics of the damage, and motor mount (after the crash).
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Old Jun 22, 2010, 01:27 AM
Registered User
Joined Mar 2010
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jholan..looked like it came down quite hard..you would probably need a new plane if its balsa.
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Old Jun 22, 2010, 06:15 PM
Ride Blue
jholen's Avatar
United States, WA, Sammamish
Joined Aug 2006
1,495 Posts
Repaired the nose last night, there is no flex now, but still had the same problem today. I think it's the pushrods - I'm guessing at WOT there is just too much force and somehow the pushrods flex and the controls flutter or flex enough to give it the downward right spin. I have some carbon pushrods and will install those and see if it fixes the problem!
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Old Jul 05, 2010, 07:26 PM
Ride Blue
jholen's Avatar
United States, WA, Sammamish
Joined Aug 2006
1,495 Posts
After multiple attempts to remedy my problem I've decided to retire the plane and use all the equipment in something else. After 7-8 different attempts to fix it, nothing works, including a complete motor mount rebuild with basswood (to prevent motor angle changes when going full throttle), as well as all carbon push-rods to prevent control surface flex.

It is just not worth the frustration of spending time repairing it only to have it have the same issue out at the field. Bummer, wished it would have worked. Maybe I got a dud. Hopefully you all have a different experience than I have. For now I think I'm going to stick with my Skywing kits.

Edit: Anyone interested in an Ultima fuse?
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Old Jul 05, 2010, 10:50 PM
EP 3D Flyer
feda's Avatar
Hamilton, Canada
Joined Nov 2005
1,029 Posts
Quote:
Originally Posted by jholen View Post
After multiple attempts to remedy my problem I've decided to retire the plane and use all the equipment in something else. After 7-8 different attempts to fix it, nothing works, including a complete motor mount rebuild with basswood (to prevent motor angle changes when going full throttle), as well as all carbon push-rods to prevent control surface flex.

It is just not worth the frustration of spending time repairing it only to have it have the same issue out at the field. Bummer, wished it would have worked. Maybe I got a dud. Hopefully you all have a different experience than I have. For now I think I'm going to stick with my Skywing kits.

Edit: Anyone interested in an Ultima fuse?
Sorry to hear your frustration, jholen.

I've read your posts but felt that I could not offer any good suggestions. The symptom seems to suggest that the airframe is somehow distorted under stress in flight, but you could not locate the cause after the flight.

Yesterday, I got the opportunity to dissect a Hokusei Cap232 EPP fuselage and had a better understanding of its construction (wood & epp hybrid). I could see the overall stiffness of the fuselage was achieved with a horizontal wood frame, a keel-like wood strip above the frame, some epp sheets, and dual-layer reinforced epp sheets. Each of these parts had different stiffness. I thought to myself that it was relatively easy to detect when the wood parts got broken somewhere but more difficult to find out when a certain epp part got damaged. The epp material is flexible before getting damaged and will not necessarily show cracks when its strength is already greatly reduced. When that happens, the damaged epp part cannot contribute to the overall stiffness of the structure.

Anyway, that's my theory. Sorry that I cannot provide more practical help.

Regards,

feda
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Old Jul 05, 2010, 10:54 PM
Ride Blue
jholen's Avatar
United States, WA, Sammamish
Joined Aug 2006
1,495 Posts
No worries feda.

I know there are a lot of happy ultima owners out there, and honestly this could have happened with any kit. I'm sure someone with more patience, lol, could probably find out where the problem is. But since I have my Skywing Tough always with me, instead of using my lipos to test/crash the ultima I always just put them in the Tough and get to flying.

For the record, I in no way think this is a reflection of your business. You've been an awesome resource and very helpful!
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