Jun 11, 2011, 12:02 AM
Argue for your limitations
ajbaker's Avatar
Quote:
Originally Posted by Prof100 View Post
AJ,

At $2.15 who'd make one? That would decouple the tail wheel from servo.

Bill
Great point. Duh. I should have noticed that. I am going to order both ideas tomorrow. That is, unless someone contributes something else to try. Anyone else want to jump in. We are moving along now is a positive direction and I welcome any suggestions. KISS is sort of the principle that Bill (I hope is OK to include you) and I are working on right now. With all the brilliant guys here, there has got to be at least a couple of other ideas. For right now, we are using Tower Hobbies. But, any hobby store is OK with me.
AJ
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Jun 11, 2011, 12:02 AM
Registered User
Prof100's Avatar
Quote:
Originally Posted by ajbaker View Post
At first glance, it does not look like it would have enough torque on the steering to keep the wheel turned. I think the caster effect might override the turning??? Hmmm... Don't know. Is that possible? Your thoughts.
AJ

AJ,

At first blush I think it would work perfectly. The servo moves the rudder, rudder turns and moves tail wheel. A HXT900 would be getting a workout. I am running 14 or 16 gram MG servos in mine. Pretty straightforward to me. The mods are dealing with the foam not being as strong as the balsa. The tail of the plane needs a piece of plywood glued in to retain plastic mount. I'd use blind nuts and 4-40 screws. Sure the tail would get heavier but the lipo would have to slid forward.

Bill
Jun 11, 2011, 12:06 AM
Argue for your limitations
ajbaker's Avatar
Quote:
Originally Posted by Prof100 View Post
AJ,

At first blush I think it would work perfectly. The rudder moves and the wheel follows. Pretty straightforward to me. The mods are dealing with the foam not being as strong as the balsa. The tail of the plane needs a piece of plywood glued in to retain plastic mount. I'd use blind nuts and 4-40 screws. Sure the tail would get heavier but the lipo would have to slid forward.

Bill
Naturally, I trust your glance more than mine in this area. The few grams of extra weight would be negligible. I have LOTS of room to move the battery rearwards. JTSHMPCT.
Oh. BTW - I used a Futaba S3101 servo (34oz. torque) for both the elevator and the rudder from day 1. The HXT900's made me feel a bit uncomfortable even though all the posts that I read say they work just fine. Now, especially, I am glad I did.
AJ
Jun 11, 2011, 12:09 AM
Registered User
Prof100's Avatar
Quote:
Originally Posted by ajbaker View Post
Naturally, I trust your glance more than mine in this area. The few grams of extra weight would be negligible. I have LOTS of room to move the battery rearwards. JTSHMPCT.
AJ
AJ,

I like the Sullivan design, I will have to order three of them. One for each FUNCUB and one for MUS I have NIB. The Mini Ultra Stick just has a skid, no tail wheel.

Bill
Jun 11, 2011, 01:14 AM
Argue for your limitations
ajbaker's Avatar
Quote:
Originally Posted by Prof100 View Post
AJ,

I like the Sullivan design, I will have to order three of them. One for each FUNCUB and one for MUS I have NIB. The Mini Ultra Stick just has a skid, no tail wheel.

Bill
While I am waiting to order those, I got started on a ground to servo disconnect. I think I am going to need stronger springs. But, I want to try it the way it is right now. The total compression of each spring is exactly equal to the throw of the servo. So, there is no way the servo can get hammered. But, flight info will tell me how much (or if) I need a stronger spring.
Next, I am going to put in a .078 piano wire tail wheel holder.
AJ
Jun 11, 2011, 01:56 AM
Argue for your limitations
ajbaker's Avatar

Progress.


I had to cut off the elevator to facilitate bending the .078 TW wire. The epoxy is setting up right now (30 min). That is enough for tonight. I took a LOT of pictures. But, this one is enough to show where I am at right now.
AJ
Jun 11, 2011, 02:02 AM
Registered User
Jurgen Heilig's Avatar
Quote:
Originally Posted by mavlo77 View Post
...
not sufficient for real hovering. So that's why I want to test this 13x6.
...
In the static test I pulled 30 seconds WOT and the motor was just warm, not hot. So was the 40A ESC. As the Funcub is not a plane to fly WOT all the time, I guess it will do fine.
For hovering, you preferably want a prop with low pitch, not more pitch.

Check the current. A 13x6" might be too much prop for your motor.

Quote:
Weight: 130g
KV(rpm/v): 1000
Max Power: 555W
Battery: 2-4Li-Po
Test Prop: 12x5/11x7
Ri(M Ω): 0.031
ESC(A): 60A
Jürgen
Jun 11, 2011, 02:08 AM
Registered User
Jurgen Heilig's Avatar
Quote:
Originally Posted by ajbaker View Post
...
I am pretty sure that the real problem stems from the direct connection of the rudder servo to the ground (stupid design).
AJ
Same proven design as used on previous MPX models, like the AcroMaster, Gemini, EasyCub and although those models have been on the market for years, you don't read about "real problems".

Jürgen
Jun 11, 2011, 02:23 AM
Registered User
Jurgen Heilig's Avatar
Quote:
Originally Posted by Prof100 View Post
...
The best planes in the world are German designs when voted on in a German RC magazine. No one should be surprised.
...
It is a vote by the readers of the magazine and of course you also find models from other manufacturers/distributors in the rankings.

Jürgen
Jun 11, 2011, 02:30 AM
Registered User
Jurgen Heilig's Avatar
Quote:
Originally Posted by Prof100 View Post
Looks rather heavy for a model like the FunCub, but if you need weight in the tail because you are running a heavy motor or FPV gear in the nose, why not?

Jürgen
Jun 11, 2011, 02:57 AM
Ozzie Express wiggy pilot
SON OF PALEFACE's Avatar
This one mite be even lighter and has springs to take the shocks , not the servo......But hey whats a few grams when you can move your lipo forward a little.....Nothing

http://www3.towerhobbies.com/cgi-bin...&I=LXHVC4&P=ML

Cheers
Ian
Jun 11, 2011, 03:08 AM
Registered User
Jurgen Heilig's Avatar
Quote:
Originally Posted by ajbaker View Post
I got started on a ground to servo disconnect.
...
So, there is no way the servo can get hammered. ...
When looking at the servo installation, I can understand why AJ had problems applying the decor, as his servo is not installed as intended, but there are also some other issues:
Jun 11, 2011, 03:29 AM
Ozzie Express wiggy pilot
SON OF PALEFACE's Avatar
Gee mate...you go to a lot of trouble to ni....er .....'help' others on these forums..

Ian
Jun 11, 2011, 03:38 AM
Argue for your limitations
ajbaker's Avatar
Quote:
Originally Posted by SON OF PALEFACE View Post
This one mite be even lighter and has springs to take the shocks , not the servo......But hey whats a few grams when you can move your lipo forward a little.....Nothing

http://www3.towerhobbies.com/cgi-bin...&I=LXHVC4&P=ML

Cheers
Ian
Talk about KISS. That is excellent. Simple build - very straight forward design. Totally decouples the servo from the any ground attacks. Great feedback. Thank you. - That is why I waited to order stuff from Tower. I will include your suggestion now. I see Jergen has a lot of posts. I feel somehow that they are not helpful to my project, though.
AJ
Last edited by ajbaker; Jun 11, 2011 at 03:47 AM. Reason: typos
Jun 11, 2011, 03:49 AM
Registered User
mavlo77's Avatar
Quote:
Originally Posted by Jurgen Heilig View Post
For hovering, you preferably want a prop with low pitch, not more pitch.

Check the current. A 13x6" might be too much prop for your motor.
Jürgen

Yes, I realize... actually I was prefering a 13x4 prop for the reason you give (lower pitch). But couldn't find it in the local hobby store (tried 2 or 3 in the past months).

Also I have a 900 kV motor available. Probably that is a better match. But then I need to swap motor when flying in rough field....

So better start looking for 13x4 (and being easy on the throttle) or 12x4 and keep the 1000 kV.

In the meanwhile I still try this prop and being very carefull on the throttle.

Will post video if I have tried it.


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