Modifying Skymaster landing gear

cessnadriver · #1 09-28-11, 06:22 AM

I'm seriously considering buying a C337A (PROJECT). Here's my question. I'd like
to convert a C337A from RG to permanently fixed gear. Does anyone know A
DAR/DER that I can give me information about this pursuit? I'd like to know the
following. 1) Is this change over possible? 2) Will I have to do an STC, or can
I just get it approved and possibly sell the information (documentation) to some
one that wants to do the same conversion? 3) If do-able, will I be able to
remove all hydraulics, lines pumps, cylinders and increase the USEFUL weight?
I'm an A&P and will do most of the work. Any and all information/advise will be
deeply appreciated!
Thanks, Bill Story 814-673-6863 bstory@pa.rr.com
PS: I've contacted Bill Crews he suggested I contact Owen Bell, haven't yet.

hharney · #2 09-28-11, 11:56 AM

This has been discussed before and I only know of one aircraft that has done this.

See this link

http://www.337skymaster.com/messages...ght=fixed+gear

Skymaster337B · #3 09-29-11, 01:56 PM

If you want fixed gear why not just buy an older 210 or even a 182. Sky masters are much better airplanes with retracted gear.

sns3guppy · #4 09-29-11, 11:34 PM

If you're going to fix the gear, I wouldn't be in a hurry to remove everything that made it a retractable gear airplane; you're taking value away from the aircraft.

If you want the gear down, why not simply leave it down?

If you're looking to put bigger tires on it, then you do have a problem if the gear remains retractable, if the tires will bind the gear. Even if you don't intend to use the gear, having tires that are too big for the wells or for unhindered operation do pose an issue. This would still be an issue for a Form 337 change.

You could seek your own STC, but it will be time consuming and expensive, and without engineering data to back it up, I don't know that you'd see a gross weight increase, anyway. You may want to partner up with a DER to see what you can arrange.

cessnadriver · #5 10-02-11, 06:36 PM

Thanks to all that left a message. I appreciate the input. I'm going to pick-up my C337 this weekend!!!! It's a 1965 C337. It may sound strange to most Skymaster 337 pilots/owners but I'd be VERY happy to have a fixed gear Skymaster. I originally was looking for a C336 that came only as a fixed gear but I found out that they are hard to come-by and that there where issues that where corrected in the C337! I talked to several experts about my plans to convert a c337 to fixed gear. Many supportive with reservations. I have tracked down the only C337 that was converted and am trying to contact that owner. If this owner of N53504 1975 C337G is a member, PLEASE contact me at either bstory@pa.rr.com or 814-673-6863 (C).

Ernie Martin · #6 10-03-11, 12:30 AM

I've been tempted to write earlier but felt I shouldn't wait longer.

IMO you should not do the modification.

Three reasons.

First, with routine maintenance the gear is very reliable. Second, once you get used to the faster speed of the gear-up aircraft, the gear-down version will seem impossibly slow -- it may be 5 or 10 knots, but believe me that it feels like much more (for reasons that have nothing to do with the gear, my last 10 or so flights have been with the gear down and it's a pain). Third, there is a safety issue, because an engine out on take-off is a lot safer to handle when the gear is up compared to when the gear is down.

I also concur with others that to do it right will be expensive; save the money for unexpected expenses and to keep your bird in perfect condition.

For the record, I've owned two Skymasters over the last 12 years (the first one was a D with the gear door removal STC and the current one is a G with the doors), I have an MS in mechanical engineering and spent over 30 years in aerospace businesses.

Just think about it.

Ernie Martin

cessnadriver · #7 10-03-11, 07:49 AM

Mr. Martin,
You probably make perfect sense? I have an unnatural fear of doing a gear up landing that I don't think I'll ever get over. The extra training required to DEAL with retractable gear, ie, emergency procedures. I am a single engine Cessna pilot, of about 400 hours, non-instrument rated, and that too is something I don't ever plan on getting (crazy especially since I'm buying a Skymaster). I returned to flying airplanes after about ten years of off-and-on helicopter flying. I'm just a "bore holes in the sky" pilot. I didn't even think I'd fly something (in my mind) as complex as a fixed gear C182. But as a CAP pilot I had to fly the C182 because of my job as maintenance officer for our Squadron. Any ways I do feel comfortable in the simple C182 with constant speed prop. SO I wanted to expand my horizons by purchasing and learning to fly a Skymaster. Back to my thoughts. I'm an A&P and will be doing my own maintenance, with help from an IA for annuals. So as a mechanic I feel the additional maintenance/expense (like rebuilding/replacing hydraulic cylinders, gear retract tests, etc.) required for the "RG" is not worth it. As I previously stated I was originally looking for a C336 as you know was ONLY a fixed gear.
This is my thinking, thanks for your comments.
BILLS

Roger · #8 10-03-11, 08:42 AM

There is certainly nothing wrong with having any given "fear", and I am sure we all have different ones. There is some talk on this board about the "fear" of engine fire, prompting a search for a system to alert operators if it happens in the rear engine, etc..

The only thing that I might point out is that the "fear" about a gear up landing is really kind of an issue that cuts both ways. In other words, in some instances you may very well want the gear up, if you need to make an unscheduled landing depending on the terrain. Over water or particularly roung terrain, you are typically better off leaving the gear up.

There are a few different devices on the market that will better alert you through your headset or speaker if your gear is not down when close to landing. Spend a little money on that type of backup system, and then you will have the best of "both worlds".

And lastly keep in mind that if you land gear up, so what. I saw a skymaster that had just done it, and all it needed for repair was a little skin work.

Good Luck/Roger

sns3guppy · #9 10-03-11, 09:25 AM

I have had several students in single engine airplanes who were afraid to raise the gear in a Cessna 210. They wanted to do the training with the gear down, on the premise that the gear might fail with use. This is somewhat akin to never wanting to bend one's knees on the off chance they might wear out, or the ancient hang gliding counsel that one should never fly higher than one cares to fall.

Raise the gear.

Yes, landing gear does fail. The Cessna gear is no exception. Like all things mechanical, however, and like all aircraft systems, there are procedures for handling failures.

The Cessna gear system found on the Skymaster has several potential fixes, from replenishing fluid in flight to pumping gear down by hand, to shutting the system off to cool. Knowing the system is the secret to getting comfortable with the system. Not knowing the system, not knowing any system, inspires distrust and fear. Get to know your airplane.

Ernie Martin · #10 10-03-11, 11:03 AM

Your concerns about "additional maintenance/expense (like rebuilding/replacing hydraulic cylinders..." I think is unfounded. Over 12 years on two Skymasters I have never spent a penny on gear maintenance except for inspecting it at annual and one time when I changed the hoses. With you being an A&P, the issue is even less significant.

Just think about it. One suggestion: buy it, fly it for a while, and then decide.

Ernie

Skymaster337B · #11 10-03-11, 09:46 PM

I have aircraft insurance for one reason...gear up landing, mechanical or cranial-rectum inversion. I highly recommend you do the same. Then you don't need an unnatural fear of retracting the gear.

cessnadriver · #12 10-04-11, 06:47 AM

To all, thank you for your comment/advise.
I understand the concept of the gear and the potential of lessening the value of my plane "IF" I decide to modify the gear. Here is another way to look at this.
Being unique! Since the bird I'm getting is somewhat a project I'll have time to evaluate the system and maintenance involved in maintaining it. I certainly don't plan on "ripping" the system out day one. I still need to talk to the DAR that approved the mod and see if in fact it will be too expensive to do? Besides what wrong with simplicity?
Thanks, BILLS

WebMaster · #13 10-04-11, 08:44 AM

Quote:

Originally Posted by cessnadriver

Besides what wrong with simplicity?
Thanks, BILLS

Nothing at all. And it will reduce your insurance costs.
I think a bunch of 337 Field modification forms will be required, but no STC. You will have to come up with a way to make sure the landing gear doesn't retract on you. This means it is more complex than just removing the cylinders, hoses, etc.

Take a look at the one that has been done, they put wheel pants on the mains.

Roger · #14 10-04-11, 09:51 AM

Or just stop thinking about it and pull the circuit breaker. Next

cessnadriver · #15 10-04-11, 12:39 PM

To Mr. Larry Bowdish,
Yes I know that I can't just remove the cylinder and related equipment. N53504 the only C337 converted to "Fixed gear" that I know of. I'm hoping to contact him PRIOR to doing any conversions. Hopefully he'll have the name of the DAR that approved the mod and or documentation that will show me what to do.
Thanks for you comments.
Cessnadriver (as of Saturday "Skymasterdriver" ha ha!)