Another MK Retract Question
 

OK Gent's,

Here's an easy one for you. Are the mounting brackets and flanges for the MK mechanical retracts and pneumatic retracts the same width? In other words, can I use my MK pneumatic retracts as a temporary substitute in the wing of my Dirty Birdy to build the supports or should I wait until I get my mechanical units?

TIA, David:D

RE: Another MK Retract Question
 

David

two questions:

1) Are you sure you have MK pneumatics? I wasn't aware that any such units existed.

2) Why use mechanicals if you have pneumatics? I realize there are reasons but are there any issues with the pneumatics?

3) What MK mechanicals are you intending to use? There were several different models. OK, that was three questions... :)

David.

RE: Another MK Retract Question
 

David,

You're right, of course.

1) I must have been brain dead when I wrote the question yesterday, the pneumatics I have are not MK's, they are Rhom Air's...[sm=spinnyeyes.gif]

2) Since there isn't allot of room in a Dirty Birdy fuselage, I thought it would be easier to use mechanicals. With that being said, If I don't get the MK's in time, using the Rhom Air's are not out of the question.

3) I cannot answer this question, because I don't have them yet. I have a set of MK trike gear retracts, but I'm going to use them in my Illusion if I can ever find time to finish it.

Thanks for straightening me out....:D

David

RE: Another MK Retract Question
 

Dave Dave Dave, there is plenty of room in a DB to use pneumatics. In fact you need less room for air retracts since you do not have to make clearance for pushrods and seros. The airtank can be stuck anywhere with silicone. On my P5, the airtank was glued in the top of the fuse behind the wing. They are so light that they have almost no effect on CG.

RE: Another MK Retract Question
 

Cool,

That solves a multitude of problems. I'll use my Rhom Air's, since I already have them.

Thanks for the help fella's....:D

David

RE: Another MK Retract Question
 

David,

No problems.

1) Rhom Air are standard not metric. The spacing between mounting holes is 1" and I forget the spacing between flanges. MK's on the other hand are Japanese and therefore metric. The lug spacing is probably not an issue but the mounting holes are probably a little different. In short, without the two units in hand, I'd guess the mounting is not compatible.

2) Like Jeff mentions, You should be able to get pneumatics into your DB. With a glass canopy, you can also use the space to install the tank there. Other than the tank, I'd say that the pneumatics require less space - one mini servo and the valve would fit on your servo installation. With four fuse servos (elevator, rudder, hear and throttle) you can put the rudder and gear in line on one side and the elevator and throttle in line on the other.

3) Based on your comment, I take it you're going with conventional gear in the DB? In this case, mechanicals are perhaps a tad lighter. Do you know what color the MK you're expecting are?

David.

RE: Another MK Retract Question
 

David,

I know I should be tarred and feathered, but my Dirty Birdy will be set up as a tail dragger since I don't have a Rhom Air, nose gear. Motor will be a NIB Super Tigre G60 Blue Head which should be just about right for my flying style.

No, I don't know what color my new set of MK's are going to be.

David

RE: Another MK Retract Question
 

:D

Sure, plucked and roasted at the stake... :)

Well, I wouldn't use pneumatics for a conventional pattern setup but there's nothing wrong with it. Then again, if you're going to use mechanicals, you can put a nose gear in it with the servo in the gear area. The flat type sailplane servos are good for those installs.

I picked up a nice sport JR retract servo recently for a conventional setup (Super Pacer). Less expensive than others and a little lighter. JR quality.

David.

RE: Another MK Retract Question
 

Well,

It looks like I may be spared the plucking and roasting....:D I dug out my set of Rhom Airs and its a complete trike gear set. Better yet, I also have the installation instructions that came with them . Well, this should be l learning experience. I'm sure I'll have some questions, but I know a great place to get my answers......;)

David

RE: Another MK Retract Question
 

but the real question is Dave, when are you going to build it?

RE: Another MK Retract Question
 

David,

good news! A DB with a trike set of Rhoms is perfect - very classic. Is it a FW or belly mount nose gear? Rhom's require a little more attention than spring down pneumatics due to the double lines but a little planning during the radio/gear install takes care of things. I'd definitely put the tank in the canopy. Once the canopy is installed, just bore out the rear canopy area inside of the fuse (or do it beforehand - even easier).

I'd say that installing retracts nicely amounts to 25% of the time required to frame up a classic. Perhaps a little less with built up wings. If you haven't installed retracts before, be patient, perseverance pays off. It can get a little monotonous to spend evening after evening working on the same area! The good news is that when the wings are foam core, the work is even more tedious. I'm assuming your DB is a wood frame.

When will you build it? Never mind, start this evening with the fin, then the stab, then the wing, the mains, the fuse, the engine, the nose gear. Before you know, a framed up DB!

Finishing it is another matter - there's the other 50% of time to get a classic airborne... :D

David.

RE: Another MK Retract Question
 

Jeff,
Very funny....:D Hey, what kind of plane was the red one Ronnie flew on Saturday? It looked like an old high wing pattern plane that flew great.

David,
I'm not going to be building the plane. I found someone willing to build it for me (man you have to love this hobby). The instructions I have with my Rhom Airs say you can mount the nose gear either belly mount or firewall mount, but the more I look at the nose gear itself, it may not be a Rhom Air unit. The metal used for mounting the mains are an orange color and the nose gear is black like the Prolines in my Dalotel.

As luck would have it, even though I'm not going to be building my plane, the construction is being postponed for a while which may work to my advantage. I say that because I may have the option of trying the new Hangar 9 electric retracts in it. WE'll have to wait and see.

David

RE: Another MK Retract Question
 

Well that simplifies things...:)

Orange metal, huh? Sounds like Robarts to me. If they have a 90 degree flange with holes on both the end and the base, then yes, you can mount it either on the FW or on the tank floor.

The 60 size E-Flites are belly only (see photo). If your builder needs some schematics for the gear install, then he can use the Robart 510W schematic:

http://www.robart.com/retracts/6-12lb510.aspx

and/or Rhom units both of which are identical in mounting pattern to the E-Flites. I'm building a Calypso and also plan to use the E-Flites (mains only). I used Rhom's to space the mount plates (yes, that is a nose gear - spacing is the same).

Enjoy! David.

RE: Another MK Retract Question
 

Dave, that plane was an RC Ringmaster ARF from WAYYY BACCKK. It was a Sterling, all balsa, pre-built kit that was uncovered. I still have the box to it at my house. I have no idea where he found it, but from what I understand, it is very rare???
He says it flys pretty good for what it is. He had a buddy's motor on it breaking it in for him. It needs a bit more power. Suprisingly, it was not a featherweight, she had a little heft to her.

RE: Another MK Retract Question
 

25% of the total time required to frame the whole plane? Wow...that's long. It used to take a couple hours as I recall after the mounting plates were installed in the wing. When I decided to fully clothe the gear with articulating gear doors and such, and actuating the whole trike gear set-up with one servo, that took 20 hours to set-up. Is that what you mean by installing a set nicely? If yes, then I agree...25% would be about right

RE: Another MK Retract Question
 

Matt,

I was probably overstating things a bit but depending on the airframe, it's a rough estimate for my building.

At the moment I'm installing retracts into a foam wing which was previously (poorly) sheeted and had maple blocks glued in for fixed gear. Needles to say, getting things cored out and removing the fixed gear blocks and supporting ribs without destroying the wing is time consuming. The fuse took 2 afternoons to get framed up and shaped. Each retract bay is needing 2 afternoons before I'm satisfied and it's ready for mounting.

Even with a fresh core though, I'd say I spend about the same amount of time (perhaps a little less), working on the core "innards" (retracts, servos, tunnels, etc.) as I do on getting it sheeted, capped and sanded. Of course, if the airframe is a composite layup or it's a complex Japanese (or a scale) design then things change. I guess I'm talking about your average '80's "box" design classic.

In short, it does take me about that amount of time to get that part of a build done - or at least feel like it does... :)

David.