Considering M20L AirMods conversion

[VA FLYER]

280 HP IO550N conversion. Seems to be useful load challenged, but since 95% of my use is with two lightweight adults, that’s not a big concession. But a couple other questions about this mod:

1. I could not find any info on possible STC increases in Max Gross weight for this model, currently 2900 lbs. Are there any?

2. How much does the rear seat weigh, and how hard is it to remove? Gaining even 40-50 lbs to the UL would be a big help. I’d rather have another 8 gallons fuel than backseaters. 

3. The throttle and Prop controls are fastened together at the cockpit end with a bar and screws. I’ve never seen this kind of arrangement. I’ve flown the early SR22 which has a pseudo single power lever that connects the two using a cam arrangement, but this is different. Is this connection required? Looks kinda Rube Goldberg to me.

Finally, any recommendations (positive or negative) on paint shops East of the Mississippi? 
 

Thanks.

[LANCECASPER]

On 9/14/2021 at 8:40 AM, VA FLYER said:

280 HP IO550N conversion. Seems to be useful load challenged, but since 95% of my use is with two lightweight adults, that’s not a big concession. But a couple other questions about this mod:

1. I could not find any info on possible STC increases in Max Gross weight for this model, currently 2900 lbs. Are there any?

2. How much does the rear seat weigh, and how hard is it to remove? Gaining even 40-50 lbs to the UL would be a big help. I’d rather have another 8 gallons fuel than backseaters. 

3. The throttle and Prop controls are fastened together at the cockpit end with a bar and screws. I’ve never seen this kind of arrangement. I’ve flown the early SR22 which has a pseudo single power lever that connects the two using a cam arrangement, but this is different. Is this connection required? Looks kinda Rube Goldberg to me.

Finally, any recommendations (positive or negative) on paint shops East of the Mississippi? 
 

Thanks.

I thought that the shop that held that STC for the M20L conversion closed years ago due to a hurricane around 2004 or so?

I don't think the rear seats weigh anywhere near 40-50 pounds.

The Porsche Mooney (M20L) had a single power lever, the conversion had to work around that.

This conversion may have looked like an Ovation on paper, but don't get fooled. It had the single puck brakes. The landing gear on this long body is from the mid-body 252 (meaning not robust enough for a long body Mooney - no way it's ever going to get a gross weight increase with that landing gear and those brakes). If it was equipped with speed brakes they were the vacuum brakes, which can be troublesome. It had the small fuel tanks, etc, etc, etc. They are nearly impossible to sell once you're done with them. The only chance you would ever have of selling it is to someone who believes they are smarter than everyone else out there looking for an airplane.

[StevenL757]

3 hours ago, VA FLYER said:

280 HP IO550N conversion. Seems to be useful load challenged, but since 95% of my use is with two lightweight adults, that’s not a big concession. But a couple other questions about this mod:

1. I could not find any info on possible STC increases in Max Gross weight for this model, currently 2900 lbs. Are there any?

2. How much does the rear seat weigh, and how hard is it to remove? Gaining even 40-50 lbs to the UL would be a big help. I’d rather have another 8 gallons fuel than backseaters. 

3. The throttle and Prop controls are fastened together at the cockpit end with a bar and screws. I’ve never seen this kind of arrangement. I’ve flown the early SR22 which has a pseudo single power lever that connects the two using a cam arrangement, but this is different. Is this connection required? Looks kinda Rube Goldberg to me.

Finally, any recommendations (positive or negative) on paint shops East of the Mississippi? 

Thanks.

To start, no one to my knowledge is doing this conversion.  ModWorks in FL were the last folks I recall doing this.  Unless you’re planning to spend gobs of money on this, it is very invasive…involving a new cowling, multiple cuts in the firewall, and other modifications.  If you’re serious about owning an “L” with this conversion, N136MP *might* be available.  My IA is willing to talk to you about this airplane.  PM me if you want his contact information and I can put the two of you together.

Steve

[bfreelove]

I own N136MP and it's definitely not available... hahaha.  I haven't seen another M20L with the Mod Works conversion for sale in awhile.  I think there are only 6 that where converted that are still flying. 

 I've taken a lot of weight out of mine so I have 700 lbs useful load.  Not great but works for me. It has Monroy tanks so plenty of fuel, and electric speed brakes.  Makes a great long range single seater, or medium range two seater.  I have the back seats removed, they weigh 33 lbs so not much gained.  It also had the single level power removed and standard engine controls installed by the previous owner. 

I've been looking into the possibility of getting the gross weight increased through a couple different ways.  Not a huge priority for me though as I don't really need it.  

Feel free to PM if you have any other questions about the L as I did a bunch of research before I bought mine.  

-Ben

[carusoam]

Welcome aboard VA Flyer…

You are going to want to pay close attention to the details when acquiring the first version of the Long Body Mooney.

AirMods, a current MSC in NJ….  Is not the same as ModWorks, the mod squad, or any other of Coy Jacob’s businesses… that were in FL…

Coy modified some really good planes… many happy customers years later.

Having an IO550 brought a new life to the under powered Porsche powered planes…

The next version of LB… The TLS got the strong undercarriage, and higher output turbo engine…

The third version of the LB is called the Bravo… many Bravos reside around here….

The fourth version of the LB is the Ovation…

 

Stay focussed on the details… there are plenty coming your way…  keep good notes.

If you like… you can edit your title… this can improve the responses you may get…

 

Best regards,

-a-

 

[StevenL757]

6 hours ago, bfreelove said:

I own N136MP and it's definitely not available... hahaha.  I haven't seen another M20L with the Mod Works conversion for sale in awhile.  I think there are only 6 that where converted that are still flying. 

 I've taken a lot of weight out of mine so I have 700 lbs useful load.  Not great but works for me. It has Monroy tanks so plenty of fuel, and electric speed brakes.  Makes a great long range single seater, or medium range two seater.  I have the back seats removed, they weigh 33 lbs so not much gained.  It also had the single level power removed and standard engine controls installed by the previous owner. 

I've been looking into the possibility of getting the gross weight increased through a couple different ways.  Not a huge priority for me though as I don't really need it.  

Feel free to PM if you have any other questions about the L as I did a bunch of research before I bought mine.  

-Ben

Thanks Ben.

Brian mentioned your airplane and wasn’t sure if you were selling or not, so am glad you showed up to “defend its honor”.  :-)

[bfreelove]

15 hours ago, StevenL757 said:

Thanks Ben.

Brian mentioned your airplane and wasn’t sure if you were selling or not, so am glad you showed up to “defend its honor”.  :-)

Brian knows my airplane well for sure!  He did the conversion at Mod Works and all the maintenance for the previous owner.  He was super helpful when I bought it and answered a lot of questions I had. 

[PT20J]

I recently weighed the back seat cushions for my 1994 M20J: 22.45 lbs. This does not include the fold down back seat frame. Not sure if the L had exactly the same seats.

[carusoam]

Updates for @VA FLYER…

1) Check on the engine controls… the IO550 is best used with three independent controls…  the original set-up was done for the Porsche engine…

3) Check in with Ben above… he is a great resource for M20L info…

4) If you don’t respond in public, people will think you have lost interest and have stopped responding… avoid doing that.

5) Overall, the first Long Body, updated with the fourth LB’s engine… is a pretty powerful and awesome flyer.

6) It’s MGTOW limitation is leg strength related… and no change available for that yet…  there is an Ovation being parted out in Europe.  You might want to research what it would take to adapt its legs to the M20L…  outrageously expensive if you are not an A&P yourself.

7) Last seen at the Mooney factory… there was a MGTOW increase in the plans for LBs…. It would be interesting to see if the M20Ls could be included in that…

Stay involved…

Best regards,

-a-

[Hank]

The only other option for L models was to make it a Liquid Rocket, right? Liquid cooling with rear radiator and matching basketball-sized air vent holes on both sides of the tailcone.

And it's a different engine, 350hp I believe. Also a half dozen or so flying. 

[aviatoreb]

57 minutes ago, Hank said:

The only other option for L models was to make it a Liquid Rocket, right? Liquid cooling with rear radiator and matching basketball-sized air vent holes on both sides of the tailcone.

And it's a different engine, 350hp I believe. Also a half dozen or so flying. 

Those were (are) awesome.  I am not speaking practical which I have no idea - but they are reported the absolute fastest Mooneys of all.  I have read reports of 260TAS which seems plausible.  They also supposedly had a few airframe mods to support the extra horsepower and speed.

[Will.iam]

There was one for sale in addison tx. A year or so ago and i called about it. The owner said The manufacturer was dropping support for the liquid cooled motor and once inventory was dried up the airplane becomes a paper weight or very expensive mod to put a different motor in.  Was one of the reasons it was priced so cheap. 

[Will.iam]

There was one for sale in addison tx. A year or so ago and i called about it. The owner said The manufacturer was dropping support for the liquid cooled motor and once inventory was dried up the airplane becomes a paper weight or very expensive mod to put a different motor in.  Was one of the reasons it was priced so cheap. 
 

here is the old link:

https://www.planesalesusa.com/details/Listing/Single-Engine-Propeller/5148/1988-Mooney-M20L-Liquid-Rocket

[VA FLYER]

Thanks to all who responded. The target airplane is going in to my shop for the annual so that should be a good pre-buy. There are several things to be done on it if all goes well, the first priority being paint. That will take a while so I may have the shop do wjth they can with touch ups of areas where the paint is coming off. That will last until the first rainstorm, I imagine. Paint shops all seem to be booked out 10-12 months. I'm still looking for suggestions on that.

It has reasonable IFR avionics so that can wait for something to break. I will have the "interconnect" between throttle and prop controls removed since I can't find anything that says its required or even authorized with the IO550. 

 

[VA FLYER]

On 9/14/2021 at 3:11 PM, bfreelove said:

I own N136MP and it's definitely not available... hahaha.  I haven't seen another M20L with the Mod Works conversion for sale in awhile.  I think there are only 6 that where converted that are still flying. 

 I've taken a lot of weight out of mine so I have 700 lbs useful load.  Not great but works for me. It has Monroy tanks so plenty of fuel, and electric speed brakes.  Makes a great long range single seater, or medium range two seater.  I have the back seats removed, they weigh 33 lbs so not much gained.  It also had the single level power removed and standard engine controls installed by the previous owner. 

I've been looking into the possibility of getting the gross weight increased through a couple different ways.  Not a huge priority for me though as I don't really need it.  

Feel free to PM if you have any other questions about the L as I did a bunch of research before I bought mine.  

-Ben

Ben,

How about real world performance numbers for these airplanes? Is 160Kts @ 15 gph achievable (running LOP)? 

Tim

[Igor_U]

1 minute ago, VA FLYER said:

Ben,

How about real world performance numbers for these airplanes? Is 160Kts @ 15 gph achievable (running LOP)? 

Tim

I wonder why would anyone consider that plane at all. The M20J can go that fast at 10 gph or so.

[bfreelove]

I've done some clean up and mods on mine (multiple antenna removals, step removal, weight reduction, added tail ballast, polished paint etc.), but it's a little faster than the Ovation book speeds.  I plan for 180 knots true LOP, fuel flow is anywhere from 12.5 - 10.5 gals an hour depending on altitude (10k - 16k).  ROP it's even faster but I always fly LOP so don't have a good sense for those numbers off hand.  Flat out and leaned for peak power at sea level it does 197 kts. 

[VA FLYER]

53 minutes ago, Igor_U said:

I wonder why would anyone consider that plane at all. The M20J can go that fast at 10 gph or so.

I don't want to start an argument, but I think you are wrong. Do you have experience with both types? Are you talking about a converted L, which essentially makes it an Ovation? I've flown Js in the past and never saw more than 170 K TAS, and that was not at 10 GPH, either. An 80HP gain means the converted L should do about 190 @ 75%. The calculation is: 280HP/200HP=1.4. The cube root of 1.4 =1.1187. Multiply that by the  J cruise @ 75% (per book) 170 x 1.1187 = 190 K for the converted L. 

IIRC, J climb rates were anemic at anything over 10,000 feet at anywhere close to max gross. With 40% more ponies at the same gross weight, the converted L should significantly outclimb the J as well. 

[VA FLYER]

31 minutes ago, bfreelove said:

I've done some clean up and mods on mine (multiple antenna removals, step removal, weight reduction, added tail ballast, polished paint etc.), but it's a little faster than the Ovation book speeds.  I plan for 180 knots true LOP, fuel flow is anywhere from 12.5 - 10.5 gals an hour depending on altitude (10k - 16k).  ROP it's even faster but I always fly LOP so don't have a good sense for those numbers off hand.  Flat out and leaned for peak power at sea level it does 197 kts. 

Good, thanks. That's just about what I calculated it ought to do for the speeds. Did you install GAMIs?

[VA FLYER]

4 minutes ago, VA FLYER said:

I don't want to start an argument, but I think you are wrong. Do you have experience with both types? Are you talking about a converted L, which essentially makes it an Ovation? I've flown Js in the past and never saw more than 170 K TAS, and that was not at 10 GPH, either. An 80HP gain means the converted L should do about 190 @ 75%. The calculation is: 280HP/200HP=1.4. The cube root of 1.4 =1.1187. Multiply that by the  J cruise @ 75% (per book) 170 x 1.1187 = 190 K for the converted L. 

IIRC, J climb rates were anemic at anything over 10,000 feet at anywhere close to max gross. With 40% more ponies at the same gross weight, the converted L should significantly outclimb the J as well. 

Before someone smarter than I sees it, I will concede that I did the calculation wrong by not reducing the HP ratings to 75% for both airplanes. It does not affect the answer. The correct calculation is 210/150=1.4. Cube root of 1.4 is still 1.1187. 170 x 1.1187 = 190. 

[Igor_U]

11 minutes ago, VA FLYER said:

I don't want to start an argument, but I think you are wrong.

No argument but my question was if your numbers are correct (160kt at 15gph) or you have a typo there... I would expect that IO550 powered plane has a higher speed than M20J.

[bfreelove]

13 minutes ago, VA FLYER said:

Good, thanks. That's just about what I calculated it ought to do for the speeds. Did you install GAMIs?

It just has the stock TCM injectors but the spread is only .2 gallons per hour so it runs LOP really nice.  

[carusoam]

Pretty tough comparisons…

If you like LBs… this is the first one…

If you have big back seaters… the LB is very comfortable….

If you carry a volume of stuff… the LB has more space….

If you like IO550s… The LB has that… see if you can get it in the 310hp version for the most performance….  280hp is pretty good too…

 

When comparing to the M20J… compare to the Missile that has the IO550(a) and 300hp…

 

When asking why somebody selected a particular model…. Instead of another… there is usually a mission difference that makes one slightly better for the end user over the other…

Maybe he likes the curtains in the back seat?

No two Mooniacs share the same opinion on different models… 

 

+1 on finding the reason the controls weren’t updated to match the engine….  Have that as part of the PPI… you might find this has been sitting without flying, or being controlled in a way that could have been hazardous to engine health…(?)

Or the existing owner has an explanation for all the quirks that come with a modified plane…

The IO550 has made a great performer out of the LB…

Good luck with the PPI… take as many pictures as you can… for reference later.   So many questions will come to mind a few minutes after she is all buttoned up….

PP thoughts only, not a mechanic or plane sales guy…

Best regards,

-a-

[Davidv]

The ovation (with a 550) will do around 170 knots on 12.5 gph.  A nice J will do 160 on about the same fuel flow of 12-13gph in my experience.  

[ArtVandelay]

The ovation (with a 550) will do around 170 knots on 12.5 gph.  A nice J will do 160 on about the same fuel flow of 12-13gph in my experience.  

You should be closer to 10gph on the J otherwise you’ll be run very rich.