countilaw

Back in the classic pattern era there were several brands of retracts on the market. Kraft, Dave Brown, Rhom Air and Spring Air. There may have been more but I don't remember them since I only used Rhom Air. Spring Air were nice because they used air pressure to raise them and hold them, and when the air pressure was removed, a spring forced the gear down and locked. The nice thing about that was if you lost air pressure the gear would extend. Unlike Rhom Air, if you lost air pressure, you hoped the grass was nice and soft because you would be making a belly landing.

I'm looking are at different web-sites for retracts and I'm not seeing much.

What are you guys using? What is the advantage of the brand you are using? Where did you get them?

Frank

dchuah

My Feedback: (1)

Good question. Been wondering myself. For the Classics, I've only been exposed to the MK brands or the Supras from Japan. They've been a lot of made in China variants sold by HK, etc which are loads cheaper. I take the point that it might be risky to use them on a nicely built kit. So, haven't done any of that although have purchased but not installed them. Lately, been toying with the idea of the eletrics from HK. Quite affordable so, am probably going to put them into a refurbished Curare 60 at some point (when I ever get round to refurbishing it).

Hope to hear more.

impactiq

My Feedback: (57)

Dave Brown retracts are pretty much bullet proof. Take the time and set them up correctly on the end points and use a good retract servo. They can be bought here:
http://www.dbproducts.com/store/sprt.htm

They are one of the last mechanical retracts being made in the .60 size and up planes since MK is no longer and B&D is gone too. Sad because they both made excellent retracts that were smaller height wise then the dave browns ones.


Spring air is also a great retract. They can be seen here: http://www.retracts.com/ Great retract for an air set. They make a retract series that is pretty much a drop in for planes that are equipped originally with Rhom Airs.



Robart retracts...... in my opinion.... are inconstant with their workmanship. They do make a good air valve that can be fitted to Rhom Air retracts if you have a good set. They can be seen here:

http://www.robart.com/store/retracts/aircraft-weight

There are a few others out there that have poped up in the last couple years that make a retract like the old Kraft ones..... but I can not think of their name.

Hope this helps.

Mark

grcourtney

My Feedback: (1)

what happened to B&D. I just saw him at Toledo 2yr ago..

Gary

impactiq

My Feedback: (57)

I wish I knew. Here today... gone tomorrow. I heard B&D went out of business about that time.

countilaw

Thanks for all that information Mark.

I have found one other set Vertigo Retracts. They are designed on the Spring-Air concept. I just don't know about their quality. Their web-site gives the impression that they are located in Phoenix, Arizona, when actually they are located in China and have 8 yes, eight research and developement employees. The picture of their headquarters depicts a multi story office building, but the pictures of the work areas look like portable metal buildings, and all the workers have their backs to the camera. DON'T THINK I TRUST VERTIGO.

After all the bad things I've read about HK, I don't think I want to order anything from them. I would pay a little higher price and stay made in the USA plan. I think I like the Spring-Air retracts. Running tubing is a lot easier than running rigid push rod for mechanical retracts. I wonder what happened to Rhom-Air. Does anyone know?

Frank

boomerik

MK retracts are still sold by f3aunlimited.com

Erik

bem

My Feedback: (1)

Hi,

You have E-flite electric retracts.
http://www.e-fliterc.com/Electronics...ndingGear.aspx

And You have also Giezendanner-Technik (in Switzerland) who has electric landing gear EL-5 (4 mm legs) and EL-5plus (4.5 mm legs) with"Schaltverstärker SV2" (available in version powered from receiver or version powered by external battery connection).
I think You can not use Google translator to get thier homepage translated from German to English,copy desired text andpaste into google translator instead.
http://www.giezendanner-technik.ch/shop/index.php
(site is in German language only)

/Bo

countilaw

I checked out those E-Flites. They are pretty cool and there are several LHS that carry them right near me. That's makes it even nicer. They are a little more expensive, not made in USA, but they are carried by my local hobby shop. Not having to run all the plumbing, air tank, extra servo, makes it even sweeter.

Thanks Bo !

doxilia

My Feedback: (3)

For electrics, there is also LADO:

http://www.lado-tech.net/en/

I've never seem them in the flesh but they look pretty nice.

There are too many mechanicals out there to list them all.

David

hook57

My Feedback: (21)

Some of the older sets can be found at swap meets and on occassion on *bay, or here too. I've acquired more than a few setsof Rhoms. Iusually I replace the o-rings, check the cylinders, etc, oil em up a tad and they work likethey did 30 yrs ago (but yes,the bellies do get thegreen stain occasionaly)! Just got a NIB set ofB&Ds a few weeks ago to add to the set I have; they're reserved for the soon to be ordered Bootlegger. The Dave Brown mechanicals are great too, as others have noted. I have a set from when they were Southern RC retracts, that I pulled out of a fairly oldTiger Tail that is now fixed gear, but they work really well when set up properly. A set of Supra(s) justsold on *bay a few weeks ago, pretty reasonable too. Keep an eye out for them Frank, you'll find something.
Mark

Dean Pappas

Hi Gang,
This last weekend, I had a prototype Robart electric 60-sized retract unit in my hand.
It looks like a winner in my book. Made me wish that modern Pattern ships still had retracts.
Regards,
Dean P.

doxilia

My Feedback: (3)

Dean,

Thanks for the info.

I heard that Robart was planning to add electric versions to their lineup. Are these entirely new designs or are they electric versions of the pneumatic and/or mechanicals they produce?

David

rgburrill

The Robart mechanicals look pretty good and use a standard servo instead of a retract servo.  One thing that concerns me about Spring Air is what if you want the gear up for transport?  Is it easy to raise the gear by hand with the air off?

BullardRM

My Feedback: (39)

If my memory serves me correctly, there used to be a "up lock" block that would be inserted into the retract mechanics. It kept the gear up for transport. Remembe seeing one, was possibly home made. Old age memory don't help. Shoulden't be too hard to figure out and make.

Dave Harmon

I dunno......
I've actually used MK green (SP), B&D, Spring-Air, Rhom and Supra.
All things considered.....the mechanicals were far more reliable and less hassle overall.

My concerns today are....
Spare parts...
Weight...
Weight....
Weight....

I think the belly mount nosegear is better because of the mounting method.
I always had problems with the Rhom nosegear. The pull-pull steering was a mess....never could get it to work correctly...unlike PP rudder....kaff...kaff....in fact, I replaced the Rohm nosegear with a B&D bellymount nosegear.....never had any more problems.
Also...the Rhom air valve never worked for me...after a couple of gear up landings and having to repaint the belly....I installed a B&D valve. It had problems too but I was able to overcome them and it was reliable after that.
They were a metal fab company in NY or NJ and the retracts were a sideline...if I remember correctly.

I thought the MK were fragile until I used them....not so...they worked great...IF I added a small servo for the nosegear and used the regular retract servo for the main gear.
The weight penalty to use a second servo was only 1oz because I used a mini servo immediately behind the retract.
This got rid of all the monkey motion linkage and it was stone reliable. You simply cannot believe how many nosegear collapses I saw that tore up outstanding airplanes. The dedicated NG servo completely solves that problem.
The MK are very nice...but...trying to find parts back then when they were popular was a problem. Hobby Lobby had some occasionally but it was always iffy. The pinion block plastic bearing and the little 'hat' shaped gizzie that slides back and forth are a 'must have' to use these units.

The B&D were reliable but big, clunky and heavy....but they worked. They were much easier to mount if you used the plastic box they provided to glue into the wing.
I started using them when Rhom Products quit making retracts. I think the guys name was Sonny Brown...located in Virginia.

Spring-Air needed to be tuned up. They went up just fine (dont forget to put the air restrictors in all air operated units or there will be sudden holes in the top of the wing).
But....they had problems going down.
There was some misalignment or a burr in the slide mechanism that the spring was unable to overcome. Sometimes a sudden negative G force would unlock them....sometimes....
Surprizingly...S-A was the most unreliable for me.
I got rid of them pretty quick.

I first used Supras in a Supra-Fly and while being a bit large and required occasional adjustment...they were probably the most reliable of them all.
I never needed a part...and that was a good thing too cuz I dont think parts were available for these offshore mfgd units...they were throwaways. Oh....and they had 4mm gear legs....bought any 4mm wire lately?
They are a bit large....the mounting footprint looks a bit larger...but the real consideration with these units is the height of the frame.
Some prior planning and consideration should be taken when planning the location in the wing.
If they are going in a taildragger the main gear will have to be forward on the wing airfoil. The thickness of the airfoil needs to be taken into consideration. The method I used was to cut the retract hole all the way through the wing.
Then sheet the wing. Then the retract touched the top skin so I added a single washer under the 4 mounting bolts. Done.
These worked well....meaning that I never had any trouble with them on 3 different airplanes.
The length of the gear legs is considerably longer on taildraggers which causes a sideways swaying motion that is worsened by the these retracts if the downlock stop is not adjusted correctly.
This consists of a steel set screw riding against the plastic pinion block. The set screw digs a hole into the plastic causing periodic readjustment .
The slides in the frame were too loose as well and added still more swaying by allowing the trunion block to have excessive play.
But....the swaying was only a concern when starting the engine. Under certain conditions the torque of the engine would prevent a full throttle runup unless a helper picked up the airplane.

Electric....I never used them back in the day. I think the Giezendanner and Kraft were available.
I had a set of Kraft electric....overnight.
They were so heavy I couldnt believe it.
I think I saw one set in actual use.
Oh...they were very slow in operation.
It was possible to have a flameout and the gear not down yet before you ran out of ideas.

Today....I dunno....I still think electric are heavy and less reliable but if the total weight gain was compared....air valve, air lines, and servo compared to one or two servos and a piece of music wire for air and mechanicals against the electrics of today.....what would be the answer?

One more thing....for an electric nosegear....what about motor reliability with the retract motor hardmounted to the rear of the firewall with a howling piped engine 1/4" away??
Yeah I know....the other servos have motors too but they are far away from that vibration and seldom fail.....but they do occasionally.

The Dave Brown look good but the mains are tall.....but apparently they are still in production and parts seem to be available.
They seem to only have the firewall mount NG....might not be a big problem but in addition to heavy vibration eating them up a firewall mounted unit...the mounting screws interfere with the motor mount.

In my view...there are a lot of things to be considered.....one of them is NOT money.

In the end....if I had to do it again....the MK are hard to beat overall.
Hold your nose...write the check...take your medicine.
You'll feel a lot better after the first takeoff.

OR....down and welded always works!

Dave Harmon

Oh yeah....thanks for reminding me....I had a couple of S hooks to go around the gear leg near the tire. The other end hooked to the retract sideplate.
To install the hooks after the flying is done I turned the airplane upside down, retracted the gear, installed the hooks, took the wing off and then disconnected the air line.
No need to retract the units by hand.

BullardRM

My Feedback: (39)

I think this "block" went between the cylinder and the mechanics. The one I saw had a "remove before flight" red streamer attached. Would have been U shaped to clear the push rod coming out of the cylinder. Make sense ?

Dave Harmon

Of course!
But I didn't do it that way.

bem

My Feedback: (1)

Hi,

I used Carl Goldberg mechanical retracts in 1970th and they never failed a single time for me. They can still be found now and then at various auction sites today. Your US top flyerDave Brown used them for many years and he claimed in C G ads in US hobby magazines they were very good (see one example below of such ad). I never had a belly landing when I had the C G retracts and I flew very very much back then. I hadFutaba FP-S8 as retract servo by the way with the C Gretracts.

/Bo

Dean Pappas

Hello Dave,
As I said, I had prototypes in my hand at the WRAMs show this past weekend, and they looked to share many parts with the new all-metal mechanical retracts.
The gray plastic ones never did it for me, but these new units felt right.

take care,
Dean

countilaw

I am totally surprised at the number of retracts that are on the market. I knew of a couple that I was not impressed with, but by putting our heads together we have come up with numerous quality products.

Now we have pattern planes becoming available, new engines that will have the power we only dreamed about in the 70s and 80s and quality retracts that are affordable.

Now if only we could get more fliers interested in pattern we could be on our way to reviving a sport that has almost become just a memory.

Frank

Dave Harmon

Hi Dean.....that sounds really good!
I just took a look at the Robart site after a long time and I was surprised at the selection and how nice the units look.
Robart has always had clean looking products so I imagine the forthcoming electric units will be just as nice.
Hopefully...they will add a mechanical set as well however I'm still concerned with the E-units overall weight and power requirements and how they are actuated....module into the reciever or microswitch or what?

Generally....It's been my experience that with retracts on models or full scale.....you have to add money till the problems go away.

I guess youse guys can tell I haven't really missed retracts since I've been flying F3a 2 meter airplanes with fixed gear....
But....there is just SOMETHING about a low pass at 180 with the ears layed back....and not a wheel in sight!

TonyF

My Feedback: (92)

I just finished changing the retracts in my H-9 Phoenix 7 to a set of Dave Brown's. Getting all three to work on one retract servo takes a little time, but once done they are super reliable and light. I used to make these work with a World Engines S-5 retract servo that probably had all of 30 oz/in of torque. Using a JR 791 that has 240 oz/in sure is a lot easier!

I'm not sure how available a trike set of DB retracts are now. When I bought my nose gear three months ago Dave said he had one or two left. Maybe if demand becomes sufficient he'll make another run.

flycatch

My Feedback: (26)

Retracts come in three varieties which are; good, bad and ugly. The wave of the future are electrics even though they are not a new invention. Pneumatics IMO are always plagued with problems and contary to what others say about electrics pneumatics also have problems with retraction and extension of the MLG. I'm using ESM electrics and so far have no problems other than the time frame for retraction and extension. ESM is coming out with a fix to shorten the cycle time and again IMO they will lead the industry in sales.