Need retract advice

Need retract advice

Post by 3Dwannabe » Fri, 31 Mar 2000 04:00:00



I'm a long time r/c pilot, but new to retracts.  I'll be putting a set
in a Sig King Kobra (going to make it a taildragger, I think), and I
have a few questions for you folks with experience in this department:

1)  Which is better overall: mechanical or pnuematic?  Which is
lighter?  Wouldn't pnuematic retracts also require a dedicated servo?

2) In reading ads, I've come across 90 and 85 degree types.  What does
this angle refer to?  Is it the arc of rotation, and if so, in what
situation would you use each type (I suspect wing dihedral may come
into play)?

3)  Are the less expensive brands such as Hobbico reliable at all?

Thanks in advance for any help you folks can give!

* Sent from RemarQ http://www.remarq.com The Internet's Discussion Network *
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Need retract advice

Post by Zben » Sat, 01 Apr 2000 04:00:00


Quote:

> I'm a long time r/c pilot, but new to retracts.  I'll be putting a set
> in a Sig King Kobra (going to make it a taildragger, I think), and I
> have a few questions for you folks with experience in this department:

> 1)  Which is better overall: mechanical or pnuematic?  Which is
> lighter?  Wouldn't pnuematic retracts also require a dedicated servo?

Depends, mechs are a little harder to install due to the linkage
involved. Pneu's have problems with air leaks some times. On an airplane
this size I would go with the mech's.

Quote:

> 2) In reading ads, I've come across 90 and 85 degree types.  What does
> this angle refer to?  Is it the arc of rotation, and if so, in what
> situation would you use each type (I suspect wing dihedral may come
> into play)?

85 degree retracts are generally used for planes with a lot of dihedral,
like WWII fighters. Combu\ined with the angle of the dihedral and the 85
degree rotation, the gear will hang relatively straight down.

Quote:

> 3)  Are the less expensive brands such as Hobbico reliable at all?

I personally would run very fast from the Hobbico retracts, they are
flimsy and will not last any great amount of time. I have a set of Dave
Brown retracts that have been on numerous planes over a span of about
ten years, and they are still giving reliable service. IMO some of the
better brands are Dave Brown, Springair, Robart and D&B. If you go with
mechanical, keep in mind they will require a specialized servo, a
standard servo will not work.

Vince

 
 
 

Need retract advice

Post by Paul McIntos » Sat, 01 Apr 2000 04:00:00


Quote:

> I'm a long time r/c pilot, but new to retracts.  I'll be putting a set
> in a Sig King Kobra (going to make it a taildragger, I think), and I
> have a few questions for you folks with experience in this department:

> 1)  Which is better overall: mechanical or pnuematic?  Which is
> lighter?  Wouldn't pnuematic retracts also require a dedicated servo?

All retracts, except some large scale models, require a servo.  Air
types can use the cheapest one.  Mechanical retracts req2uire a special
servo that costs at least $35 for a cheap one.  Weight is very similar,
with air being slightly heavier.  One thing to remember is that Spring
Air units are built much more durable than most mechanicals.  For ease
of installation and reliability, I choose Spring Air.

Quote:
> 2) In reading ads, I've come across 90 and 85 degree types.  What does
> this angle refer to?  Is it the arc of rotation, and if so, in what
> situation would you use each type (I suspect wing dihedral may come
> into play)?

You got it.  It is to make up for larger dihedral angles so that the
gear hang straight down without going through the top of the wing when
retracted.

Quote:
> 3)  Are the less expensive brands such as Hobbico reliable at all?

I have heard far too much negative about them to even consider them.  If
you want mechanicals, go with Dave Brown or Supras.  For air, I wouldn't
bother with anything but Spring Air.  The others are OK, but are more
complicated to set up and if you lose air pressure, you can't get your
gear down!

Quote:

> Thanks in advance for any help you folks can give!

> * Sent from RemarQ http://www.remarq.com The Internet's Discussion Network *
> The fastest and easiest way to search and participate in Usenet - Free!

--
Paul McIntosh
Desert Sky Model Aviation
(877) 311-3759 (toll free)
(602) 780-9005 (in AZ)
http://www.tcfb.com/desertsky
 
 
 

Need retract advice

Post by RetractL » Mon, 03 Apr 2000 05:00:00


Avoid Hobbico retracts.  They need to be rebent or adjusted after most flights,
very fragile.  They wear out very quick and need to be overhauled. Use a better
brand, you'll be happy.

Hobbico stuff in general is aimed at at the budget mined modeler.  The product
quality and overall design usually show this.

Mechanical are harder to install require the special 180 degree servo with the
advantage of being no fuss at the field.

The air units are much easier to install, much easier! I never have used Air
spring but it makes sense.  
LEE