ARI vs LASAR cowl closure Mod

[Mooney65E]

I picked up approx. 3 kts after having the laser cowl closure installed. I added silicone to a number of small cracks in the doghouse temporarily until new sheet metal was fabrcated to keep temps down. I'd like to get rid of the doghose completely and replace with a modern shroud. Anyone know if that's legal?

[Ned Gravel]

I think the Lopresti cowl mod and the SWTA one both come with an STC that allows the replacement of the doghouse for all models that still have them.  I do not think either the ARI cowl STC includes it and I do not think the LASAR one is STC'd yet.  Otherwise, at least in Canada, simply replacing the doghouse with the more familiar baffling is not legal outside of the "owner maintenance" category (non-certified aircraft).

One of the other advantages of changing over the doghouse to the other baffling, is the movement of the oil cooler to behind number 4 cylinder.

[DaV8or]

Quote: philipneeper

its weird how you close the opening and get cooler temps.. i realize ur forcing more air into the compartment, but what happen to bigger is better?

[philipneeper]

Quote: DaV8or

The way it was explained to me was, the exiting ports (cowl flaps, ect) are so much smaller than the intake that a turbulant bubble of air forms at the front of the cowling. This bubble of swirling air causes drag as air tries to go over the cowl and causes the front part of the engine to get hotter because the cold air isn't flowing by, it's just going around and around before finally exiting. By matching the intake with the exhaust, the bubble gets reduced or eliminated and the stream of cold air is continuous across the cylinders with minimal back flow. The cowling openings are sort of a Goldilocks sort of thing. Not too big, not too small, but just right is the way to go.

[DaV8or]

Quote: philipneeper

 so the lasar cowling closes the gap so it equals the air flow thru the cowling instead of out and around?

[KJATCt]

Ok so I have chosen the SWTA 201 cowl. I have the new engine and baffles in place. I have not flown it of course but I do like the engine accessibility this set up offers vs the “doghouse”. The fiberglass cowling should be here in about two weeks I will post more pix then.

[DaV8or]

Quote: KJATCt

Ok so I have chosen the SWTA 201 cowl. I have the new engine and baffles in place. I have not flown it of course but I do like the engine accessibility this set up offers vs the “doghouse”. The fiberglass cowling should be here in about two weeks I will post more pix then.

[KJATCt]

Quote: DaV8or

I don't have any experience otherwise, but the SWTA 201 cowl is what my plane has and it seems well done and performs as advertised as far as I can tell. IMO, it's a great compromise between a real 201 cowl or the Lopresti and a simple closure mod. It really does make it look like a 201 and therefore, pretty cool.  I think you'll really like it.

[DaV8or]

Quote: KJATCt

 How are your temps, speed?

[MooneyMitch]

"Ok so I have chosen the SWTA 201 cowl. I have the new engine and baffles in place. I have not flown it of course but I do like the engine accessibility this set up offers vs the “doghouse”. The fiberglass cowling should be here in about two weeks I will post more pix then."

Hi James.

Thanks for posting your latest photos.  We are all looking forward to the final product, your photos and your report on all.  Very exciting!  I wish we had the funds to do what you are doing.

 

 

[KJATCt]

Fiberglass took a bit longer than I thought however, it is here now and work continues. We (my IA an I) are now cutting the frame out of the old cowling. The bottom frame still needs a bit of trimming. The fiberglass will be riveted to it. Here are the pix so far, more to follow...

[Urs_Wildermuth]

Guys, small question from Europe.

I own a 65' C Model and am looking for a possible closure or other cowl mod. Problem is, in Europe EASA does not reckognize any US STC's per se, but one has to do one's own here at tremendous cost unless someone else has already done one.

I am looking at both the ARI mod and the SWTA cowl closure or 201 mod and have a few questions.

First of all, any members here from Europe who have any of those installed? If so, on which airplane? I'd like to get in touch.

Secondly: The SWTA lower cowling closure, what is the effect? Do I still need the doghouse with it? Does it do something for speed? Otherwise, it would look to me as a economic way to get a closure done. Again, any info on installations in Europe would be highly appreciated.

I have been looking at the LASAR ones as well, but am reading here that they do not do much for speed?

 

Many thanks and best regards

Urs Wildermuth

hb-dwc /Switzerland.

[Lood]

I think the only difference between Lasar and SWTA's closures are that Lasar's is aluminum while SWTA's is composite? Otherwise they seek pretty much exactly the same in terms of looks. In my personal case, I did not experience any gain in speed. My engine runs cooler, which is the main reason why I did it and it looks much better than the original gaping cowl opening.

I'm sure that the ARI cowl closure, which resembles the 201 cowl, would certainly have a small speed advantage. It seems that the best mod on the vintage models in terms of speed is the 201 windshield.

[podair]

re Europe STCs , have a look at the German LBA site , there are a couple of Mooneys there that went through the full Mods from SWTA and Lasars, so you can use that approval now on any EASA regulated aircraft and save the minor major mod paperwork ripoff... Basically, the game is to find an aircraft that has been approved already, be it EASA or the national authorities before that, and you can use that approval.

I have the full links and details somewhere, as I am looking to do a few mods to my OY-reg M20F , possible a cowl closure and windshield. 

 

[Urs_Wildermuth]

@podair

Hi, thanks a lot. Yes, please let me know the links. ARI have so far been able to tell me one "F" which has their closure, but that won't do for a "C". The LASAR I found in the German LBA, whether this STC is still accepted by EASA without the minor or major change, I don't know. And yes, to find an identical aircraft which has been approved is exactly my aim. Same goes for the Monroy Tanks, but also there the LBA has a STC. Just will EASA reckognize that?

SWTA has an STC at the LBA for the 1/4 inch single piece windshield FYI, but I think this is not the 201 style one. I do also know of an "E" here in Switzerland which has some mods, unfortunately I can't get in touch with the owner to find out which, but they are fairly old. So heaven knows if they are still available.

[DaV8or]

Hey KJATct, How's that SWTA 201 cowl coming along?

[podair]

the way EASA works, afaik,  if a mod has been approved in pre-EASA days by the national authorities, that approval can be used anywhere within EASA now without any further minor major mod application necessary. Just dig out the appropriate reference and you are ok, no need to apply or pay anything. At least that is my understanding of it. It is probably the single most (or only!) advantage EASA brought us! So spend some time trawling the various national websites, the CAA in the UK and the LBA have the most info there, and see if it has been approved somewhere. For instance I installed an EDM700 in my aircraft using a UK CAA approval that was applicable to any aircraft within the US STC (there was also a guy in Germany selling his approval for a fee, but this was free). However be careful some approvals specify a specific model or even a single specific registration (the DGAC in France did that a lot, ie 'only applicable to F-ABCD serial no 123'.

US Mooniacs, sorry for confusing you. Basically in Europe, everything is regulated by EASA now and US STCs are not automatically accepted. So you have to apply for a minor mod for a simple mod, like changing an instrument, and pay $300 fee and 10 pages of paperwork, or have to apply for a major mod for $5k plus and tons of paperwork if it is anything more than something that is only a logbook entry in the US!

Mooney EASA mods I have found approval for:

- Lasar , SWTA and MT Propeller, STEC autopilots 

Mooney mods I am trying to find approvals:

- overhauling the panel in a 6 pack arrangement for the pre 70s ones

- PowerFlow exhaust. I have found an F-reg M20E with it, but have yet to contact the owner. Btw that guy has a ton of mods on his, a full 201 cowl etc  , and goes 160kts+. We share the same mechanic, if I contact him I ll ask him about his other mods too. However I suspect he imported a fully modified Nreg M20E and then went F reg, which is a blanket approval, but we cant use it for specific mods.

 

 

[KJATCt]

The after pics!

 

I still need to finish the painting. I do like the looks and I seem to have picked up about 7-10 knots. This is between a new engine, Top Prop, and the cowl so how much speed the cowl added is anyones guess.

 

 

[DaV8or]

Looks good! Hard to know how fast you'll go yet. I'm assuming you're still breaking in the engine.

[KJATCt]

Quote: DaV8or

Looks good! Hard to know how fast you'll go yet. I'm assuming you're still breaking in the engine.

[MooneyMitch]

Congratulations James!  Wowie, zowie that looks terrific.  You've got such fun things on that airplane now.  Fly it up here December 4th for the Oceano [L52] Toys for Tots event [just bring a new unwrapped toy for the kids]. 

Happy flying!