Bob Runge's Cowl Latch Safety Device

I know that you will love this one. I was just looking at some of the beautiful Swifts in the photo collection that is part of the Swift pages when I noticed that the information describing N8888, Bill Whenchel’s airplane, indicates that he is utilizing the cowling from a GC-1A (85 H.P.) Swift modified to go on a GC-1B (125 H.P. & +) engine. It sure is a fine looking machine. But, this trick was done in about about 1953 by my buddy Joe Zito of Baltimore, Md on Swift N90806 when he installed a C-125 engine in his “85” Swift. It worked out so good that when I modified N90305 I did the same thing, except I got caught by the FAA’S man in Maryland, Inspector W.G.”Bill” Kelley. It was necessary for me to get a Supplemental Type Certificate (STC) to get it back in the air. I was issued STC No. SA1-82 in 1957 to cover the installation of a Continental C-145-2H and the cowl modification, on the GC-1A airframe. I don’t think that anyone would have a use for this certificate now, but if someone needs a copy I will be more than happy to E-Mail it to them.
Larry Simms (larrys@abs.net)

I need a set of steel cowl hinges for my 1948 Temco GC-1B. I have aluminum hinges and have had to reinforce both due to cracks. I want to convert to steel hinges. Anybody know of a source? Steve Roth N2397B

Steve: I don't know who might have some, but I have fabricated them. Make a paper pattern. Transfer it to a sheet of 4130 the same thickness as the aluminum hinges. Cut out on a bandsaw and drill the hinges, break 90 degrees same as the old hinges. -- Jim

Subject: Re: Exhaust Stack/Cowl Clearance
To: Richard Aaron <raaron@pica.army.mil>
In the course of doing some cosmetic surgery on my cowl, I'm cleaning-up the openings which the exhaust stacks pass through. What gap is sufficient to allow for engine vibration while minimizing air loss? Are there any ways to provide a seal (with a floating aluminum "washer" around the stacks and inside the cowl or fiberglass maybe)? Also, I have the original style latches which don't totally thrill me. Is there any history of problems with these or any hints for adjusting? I have 1 or 2 ideas for adding a safety. Has anyone come up with something before? Also, I'd like to add a quickdrain for the oil; do you know the thread size and if they're available (from Data Plate: C125-2, Quote Engine Number 8186-8-2)? I've also wondered about the nomenclature difference between C-125, C-145 and 0-200, 0-300. Is the C-125 equivalent to an 0-200 and a C-145 equivalent to an 0-300? Lastly, I'd appreciate an e-copy of the 0-300 manual. By now you can probably tell, I'm having a slow morning at work!

You probably want certain amount of leakage around the exhaust stacks which would allow heat to be dumped overboard. Having said that, I did rig up a stainless steel floating seal once which I'm sure cut the air loss and did not appear to cause much of a rise in cyl head temps. My present Swift is all stock and is not optimized, but I'm just content with it the way it is. The stock latches have come open and caused the loss of several Swifts. I also have the stock latches, but I safety wire the front two for every flight. You want the detent to lock in positively when latching. But I still safety wire them! The C-125 and the C-145/O-300 have a different thread for the oil drain. I'm sorry, I can't tell you off hand which one you might have, besides, I think some 125's had the same thread as the O-300. You'll just have to look at what you've got. The 125 is like a 6 cylinder 85, both engines have the same stroke. (3 5/8") The O-300 and C-145 are like a 6 cylinder O-200, they have the same stroke. (3 7/8") -- Jim


Subject: Swift Cowling
From: Ed Lloyd <edlloydaustin@juno.com>
Howdy Jim.
Recently I've noticed the top cowling on 3856K raises up 3/8 to 1/2 inch in flight on the rear at higher speeds. The part that moves is between the center hinge point and where the cowl starts to curve down around the outside of the fuselage. I have the original Swift cowling. I raised the cowl and looked it over good and it appears that the problem is created by air pressure from within due to the updraft cooling on the O300. The angle stiffeners along the inner trailing edge of the cowling appear to be too weak and the inner pressure is pushing the cowling upward in flight. At rest on the ground, the cowling fits reasonably well. Question is, have you seen this problem and do you think thicker or stronger aluminum angle in this area would correct the problem? Ed Lloyd

The easy way to fix this is to simply put a short section of common garden hose over the bolt extending out from the firewall that the hooks grab from the top cowl. If the cowl persists in riding up, a hardware store spring can be rigged up to pull it down. As a last resort, a couple of Dzeus fasteners can be installed in the top cowl aft edge. -- Jim

From: Richard Aaron <raaron@pica.army.mil>
Subject: Re: Exhaust Stack/Cowl Clearance
As to the original cowl latches, this is the only thing keeping me on the ground now. I have them off to try to work out a safety. I wanted to clarify weather past failures were due to them just opening or if there were part failures. Right now I'm intending to prevent them from unintentionally opening, but if part failures were involved, I might opt for a completely redundant latch (looks like it had some previously). Originally, there were no detents so I filed some at the bottom of the "grooves", which helped a lot. I am also curious as to exactly how you manage to safety-wire them. Thanks again.

I have some AN3 bolts installed near the latches, one nut on each side of the cowl skin. I have some small holes drilled in the latch handle, but you can just as well wrap the wire around the handle. The latches just open, the failures have been with the aluminum hinges between the top cowl halves, these should have been replaced by steel parts years ago. If you have aluminum hinges, I strongly suggest you replace them with steel. These used to be available (cheap!) from Univair, but I suppose fabricating your own from 4130 or any steel is the only option today. (I just had a friend make me a pair last week) I have also rat-tail filed detents in my latches. What happens, an airplane is out of service for a number of years, then many times when it is put back in flying condition an AD note or service bulletin gets missed. Those hinges never were an AD note and they never made the "official" service bulletins, as published. I rebuilt s/n # 8 some years ago and it had not flown since 1952, several old AD notes had not been complied with.-- Jim

Swifter Bob Runge wrote the following on the Yahoo Globe Temco Swift Club site...
"Been reading about the stock cowl latches coming loose in the Internet News letter etc. and thought I'd share the setup N80528 has on the latches. My stock cowl latches have small holes drilled in the handles. Then when closed, the latch handles bump into small studs that also have holes in them. These studs are mounted at the very end of the latch handles detented travel. Then, through the holes is put a cowl safety pin (Aircraft Spruce new catalog page 98 item #AN 416-1 or -2. The pin latches just below the through hole side of the stud, therefore not allowing any upward travel. It's clean, neat and easy to deal with going in and out of the engine compartment." Bob Runge <ejectr@javanet.com>

(Click Here to see photos of Bob's latch safety device...)

Swifter 77759, as well as the folks he referenced, are correct, a large portion of parasitic drag of a reciprocating engine powered airplane is cooling drag. The two rules on mods to my plane (N3378K) have been 1) no new holes in primary structure or difficult to replace parts (wing fairings, engine cowl etc.); 2)no visible changes to the exterior (well, from ten feet or so).

As well as the usual holes and loose pieces, three of the major leaks on the Swift cowl are around the exhaust stacks (inside the high pressure volume internally and close to the lowest pressure areas on the cowl externally), behind the spinner (leaking out of both the upper and lower plenums, as well as between them), and around the carburetor heat dump vent on the bottom. I built silicon baffles (the blue stuff) for these areas, using nomex cord between the stacks and have noted minimal deterioration in a couple of hundred of hours over the last two and a half years. I noted even larger gains than 77759 when I accomplished these changes, with cruise speed up from 130 to 145 at 8,000 feet or above. Rebuilding the tired engine at the same time likely helped a lot too, unfortunately making separation of the two effects difficult. I gained an additional 5 mph and 80 RPM at max power at 3,000 feet by adding a control to the cooling flap and an exit ramp onto the lower corner of the firewall. From an old NACA report on jet thrust from the piston engine exhaust I calculated there is about 12 lb. of thrust (about 5 hp. at 150 mph) lost do to the strait stacks. With suitably shaped ejector nozzles an additional 2 or 3 mph could result. The major gain, however, would be an increased rate of climb, up about 60 feet per minute, and best rate of climb speed would be biased up a couple of mph to boot. I haven’t gotten beyond the analysis/sketch point on this mod and it would violate rule 2, but it would look cool (P-47 like) and would bolt on/off, so fudging may be in order.

The other major drag source is the “goofy, toothy grin. It’s much too big (by a factor of about three) and it’s spread out all over the pressure distribution around the front of the cowl. It would be interesting to tuft the grill and see if air is exiting the cowl at the upper outboard areas. Anyone have any data? Unfortunately it is out of the question for me as the whole character of the airplane would be changed.  As Lopresti says, “Fly fast, life is short” or something to that effect.
Jared Smith, WA (jedswift@aol.com)

MATERIAL GUY...  (12199)
Subject: Re: Baffle Material
From: Bud England <Dalswift1@aol.com>
What are you using for baffle material on original cowls? The red,orange and blue silicone stuff seems too pliable. The old black stuff with the fiberglass thread--well, I was never convinced that it sealed that well. I really want to seal it up the best I can. -- Bud

Joe still has the original type down there. When I put my new engine in a couple of years ago, I bought a set of the original baffle seals from him and used some of those and some newer stuff in several locations. Like you say, some of that silicone seems a little too pliable, but I think you can figure out a combination that will work out. -- Jim

Subj: handle needed
From: marvin@accesstoledo.com (marvin-h)
Jim, I need a part. If anyone has a cowl closing handle for a stock cowling, I need one. One of mine broke real bad, not repairable. You do not fly without the cowling latched down so I need one real bad. -- N80740 Marvin Homsley

If it is the handle that is broken an interior handle from an antique auto may substitute. I think a 1934 Ford used much the same type handle. If the steel hook is damaged it might be repaired by welding or maybe some kind hearted Swifter has a used one and he will offer it to you. -- Jim

From: vincelc
Subject: Stock vs modified cowl [Yahoo! Clubs: Globe Temco Swift]
I've seen Lycoming and big Continental powered Swifts with either stock cowlings or Corben or other style cowlings. How much speed improvement does a modern cowling make for a given engine installation?

A clean downdraft cowl CAN help give a speed increase, but there is not much difference. A stock cowl with a baffle for downdraft cooling will be very close to a fiberglass cowl in speed. SuperModified cowls such as the one Scott Anderson put on N80555 or the ones Jack Nagle made up with the round inlets go pretty good. Also, the SwiftWorks modified stock cowl with the downdraft nose seems to work great. A stock 145 with a stock cowl may be faster than a cleaner downdraft cowl 145 because the carburetor is located in the high pressure cooling air plenum and the engine may simply be getting more manifold pressure. -- Jim

MORE COWL STUFF... (080301)
Subj: Cowls
From: Doc Moore <darladoc@sport.rr.com>
3817K's 180 Lycoming is getting an overhaul and while that's going on I would like to change cowls. I was emailing with Sam Swift concerning his cowl and he says the paperwork indicates that its a Swiftech. Can you tell me who made or makes that cowl? A fellow in Florida has a brand new cowl for sale but he doesn't have the paperwork on it. I have seen some cowls with no scoops on them that have carburated engines so am wondering how the induction system is plumbed. Do you have any knowledge of this? Thanks for your help. Doc Moore

I think yours is a Swifttech, so you all ready have the paperwork. Hank Rill has one, (727)797-1008. Also Jon Breese has one, (402) 697-8302. Be aware there are different styles for Continental and Lycoming engines and there is also one with no carb inlet for fuel injected TCM IO-360. The only versions that were STC'ed were for the 145 Continental and the 150 Lycoming. Swift Alterair in San Diego made these cowls, I don't know if they are still making them or not. They had a link off the Swift site. The last phone number I had for them was (619) 463-9057 home and (619) 565-2131 work. (Frank Verbeke) -- Jim

Subj: Corbin cowls
From: Larry LaForce <LaForce55@aol.com>
I have a question about the Corbin cowlings. How much heavier are they than the stock Swift cowl? I know they have to be some heavier because of their age and the glass techniques of that era. I'm sure the modern fiberglass cowls might be a little more inline with the stock weights. I was admiring the pictures of Mick's and Bruce Ray's birds with the Corbins on them. Thought that might be something I wanted to pursue and I thought you could enlighten me a little. Ed told me that is the reason he stayed with the stock cowl is because of the weight. Thanks and hope you are feeling well. Larry >>

The Corben cowls are "a little" heavier than the stock cowl but I never weighed them to determine exactly how much. They are made with a quality fiberglass and I think are quite comparable to newer airplanes with fiberglass cowlings. Mick Supinas hanger neighbor has a new Cirrus and I think Micks cowl is just as good. I prefer the stock cowl if it in good shape but the Corben (Alterair) is more efficient. We had both a Corben Cowl and a somewhat worn original cowl for Micks airplane and we had to choose between the two. We used the Corben Cowl because we had the whole installation, baffles, oil cooler, etc. We had a chance to sell the 125 engine we had, but only if we included the original cowl. (C-125 engines are not easy to sell!) I would not worry about the added few pounds of weight. Alturair may have lost their PMA to make the cowlings. If you are interested in one, call them, their number is on the Swift site. -- Jim
(Alturairís contact is Paul Ross <ross9290@aol.com>1405 N. Johnson Ave, El Cajon, CA 92020, (619) 449-1570)

Subject: Re: May #1 GTS Internet Update
From: Mick Supina <masupina@mmm.com>
Someone a few months ago was interested in the weight of a Corbin Cowl. During my recent annual I weighed mine. I can't remember who needed/wanted that information. If you could publish or pass along the information, I would appreciate it.Top piece: 12 pounds. Bottom section: 18 pounds. Total weight of cowling: 30 pounds. -- Mick Supina