All mid body gross weight increase

[Tim Jodice]

In a thread about @Trailboss selling his M20J, @ArtVandelay brought up a good point. What would it take to make all mid bodys able to have a 2900 gross weight?

Is it mainly paperwork? If it is a structural change what is it? Can the parts be bolted on? If not would it be practical to add (rivet?) the reinforcement to the existing airframe? 

I agree with @ArtVandelay , I would be willing to spend alot of AMUs to get the GW increase.

 

 

[Niko182]

I think it's mainly paperwork. for example, look at the A36. They have a max TO weight of 3600 lbs, with 285HP or 300HP. If tips are added, that weight can go up to 4024 lbs if you buy the paperwork and have an IO550. The tips don't add anything to help the plane fly. Its all just paperwork.

I'd also probably bumb the GW for the 180HP variants to 2740, and the 200HP variants to 2900lbs. Most C's and E's seem to have a decent useful load already, so bumping it up 350 lbs might be excessive. I have a great useful load and wouldn't give it up for anything. I run out of space before I use up my useful load.

[kortopates]

I really forget the details on this, but I recall it was after some changes to the steel cage. How significant I have no memory of. There were some J's that came out after the cage changes but before the factory increased the gross weight. Only those Mooney's where eligible for the increase.  Hopefully someone with better recollection will come along. But any increase in max gross weight is a significant engineering changes with required performance data,  load analysis and flutter analysis that some others here could better explain.

Edited December 27, 2020 by kortopates

[carusoam]

There is a bit of confusion behind these MGTW number details...

Follow along for a moment...

1) there is a serial number where Mooney changed the dimensions on a couple of tubes in the iconic steel frame...

2) with the mechanical tube change, came the GW bump... all nicely documented...

Now for the tricky part....

3) Along comes Rocket Engineering with a team of STC writers, and brilliant engineers....

4) The STC covers all M20Js...

5) For about 100amu you were able to buy the STC, get an IO550, and raise the MGTW.... without changing any tubing...

6) If you knew this, would you have spent the dinero?

Questions that come next...

7) Did RE know this?

8) Did the FAA know this?

9) Does it matter now?

10) You could weld in the necessary tubes if desired...  but, would this net you the ability to use the new MGTW number?

11) You could get RE to re-open the manufacturing of new Missiles and use their STC...  they will do that for a minimum order quantity... (I believe that is documented around here somewhere...) 

12) Let’s say you had a dozen really good aviation lawyers... they lay out the argument that the RE birds got a MGTW change without changing tubing... and it is only fair that your bird, with the older serial number, deserves the MGTW of all the RE birds...

13) Expect your lawyers to get back to you with... all you need now is the IO550 and the paperwork, and you are good to go!

14) expect to bump into one or two or three technical challenges...

• The physical strength issue (probably more of a marketing ploy, looking back on it)
• The performance issues (100 extra hp really washes away T/O and climb issues)
• The paperwork (RE has it, nobody else does...)

15) Compare to long bodies that are sitting on a very similar airframe...

16) get your legal Eagles, STC writers, and engineers warmed up....  Jonny and his team is getting ready to re-write history regarding the MGTW of the existing Long Bodies.... 

17) Why stop with Long Bodies, when there is a significant number of mid bodies that may like to see a similar MGTW bump...

18) Expect that there are a lot of details to be updated... it is quite a ways from J to M20L to M20M... many small details were updated.... including landing gear... (don’t be discouraged)

19 ) Additional info about some of the known additional details are given by Job below... (aka M016576)

Check my facts... I’m only a PP, not a mechanic, or legal Eagle... my price figure is merely a guess, for a reference... 

 

Go Rocket Engineering!

Best regards,

-a-

[Hank]

27 minutes ago, carusoam said:

 Go Missile Engineering!

Best regards,

-a-

Rocket Engineering, Anthony. Rocket Engineering . . . .

[carusoam]

43 minutes ago, Hank said:

Rocket Engineering, Anthony. Rocket Engineering . . . .

Oooop! May have had a slip up....

I was thinking about starting a new company... called Missile Engineering.... 

We could increase the MGTW of all Mooneys... one at a time...

May need an engineer, an STC writer, Chief pilot, and a sales guy....   

PP dreaming out loud, not actually starting a company...

Best regards,

-a-

[M016576]

In my Missile STC paperwork, a few landing gear components are swapped out with parts from newer J/K model aircraft in order to get the 3200lb max gross weight for the missile.  I think you could probably find those components on the used market for under $500 in total.  I posted those pages a while back in another thread regarding this exact same idea.  I really don’t think it would be difficult to up the Max Gross on the J... you just need a DER to commit to the test program/profiles. 

[Tim Jodice]

9 hours ago, M016576 said:

I really don’t think it would be difficult to up the Max Gross on the J... you just need a DER to commit to the test program/profiles. 

I think it would be easier for Mooney to do the paper work and then make money off a kit than it would be for someone to do it on their own with a DER.

I dont know how hard it would be for them and @Jonnyhas said that they are short on resources but I think it would be easy money. Not because it is necessarily easy to do but because so many people would buy it. 

[M016576]

1 hour ago, Tim Jodice said:

I think it would be easier for Mooney to do the paper work and then make money off a kit than it would be for someone to do it on their own with a DER.

I dont know how hard it would be for them and @Jonnyhas said that they are short on resources but I think it would be easy money. Not because it is necessarily easy to do but because so many people would buy it. 

I totally agree with you- but requests in the past have fallen on deaf ears- lots of speculation why.  
 

actually- it should be relatively easy and not particularly time consuming at least for the 2900lb weight, as all the test data has already been vetted.  So it would literally be a matter of proving that the changes made to allow for the 2900lb increase are valid.  You could probably write the entire STC without flying a single additional test flight... it would all be paperwork.

[Ron McBride]

As a former owner of an F, in my humble opinion with a useful load of over 1000#’s.  I did not need another 160# useful load.  
would the airplane handle it, yes.    Add density altitude to it, it would be just so so.  I rejected one takeoff and spent the night in Gallup NM.  I was well below gross weight, approx. 450#’s below gross.  The next morning, 15* cooler the plane wanted to fly and we went.  
Most of my flying was in the western half of the country.  Home base was at 2250’ with mountains around and summer density altitudes of 5000’. 
Just an old conservative pilots opinion. 
 

 

[Tim Jodice]

45 minutes ago, Ron McBride said:

As a former owner of an F, in my humble opinion with a useful load of over 1000#’s.  I did not need another 160# useful load.  
would the airplane handle it, yes.    Add density altitude to it, it would be just so so.  I rejected one takeoff and spent the night in Gallup NM.  I was well below gross weight, approx. 450#’s below gross.  The next morning, 15* cooler the plane wanted to fly and we went.  
Most of my flying was in the western half of the country.  Home base was at 2250’ with mountains around and summer density altitudes of 5000’. 
Just an old conservative pilots opinion. 
 

 

Totally agree in that situation. That said as I type this the density altitude is -1400 at my (MHT) home airport. 

[EricJ]

3 hours ago, Tim Jodice said:

I think it would be easier for Mooney to do the paper work and then make money off a kit than it would be for someone to do it on their own with a DER.

I dont know how hard it would be for them and @Jonnyhas said that they are short on resources but I think it would be easy money. Not because it is necessarily easy to do but because so many people would buy it. 

I think if it were easy it would have been done the same time as the GW increase for the higher serial #s.   It's been identified here a few times that there is a difference in the steel cage, either the wall thickness of a particular bar or some other change.    It's definitely the sort of thing that can be done, but not just a paperwork change.    The weight of the rudder balance changes as well.

 

[ArtVandelay]

I think if it were easy it would have been done the same time as the GW increase for the higher serial #s.   It's been identified here a few times that there is a difference in the steel cage, either the wall thickness of a particular bar or some other change.    It's definitely the sort of thing that can be done, but not just a paperwork change.    The weight of the rudder balance changes as well.

 

But didn’t the support bar change happen long before the change in J’s max weight? I wonder if they did it for the K models (Encore?) and just to make manufacturing easier incorporated that change into the J as well.

[PT20J]

The gross weight change happened at S/N 24-1686 which is coincidentally when the wall thickness for the lower tubes was increased. Since these tubes can be prone to internal corrosion (it’s the one called out in SB-208 for inspection with a magnet) perhaps someone has had experience replacing them. Looks to me like the wing might have to come off.

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[jlunseth]

Why stop at 2900, why not 3200. My understanding, admittedly limited, is that the issue is the landing gear, and there have been several upgrades to 3200 by changing that, the Rocket Engineering modifications being just one example. Was the Encore not also an upgrade to 3200, or at least something over 3,000. 

[Niko182]

5 minutes ago, jlunseth said:

Why stop at 2900, why not 3200. My understanding, admittedly limited, is that the issue is the landing gear, and there have been several upgrades to 3200 by changing that, the Rocket Engineering modifications being just one example. Was the Encore not also an upgrade to 3200, or at least something over 3,000. 

3200 lbs for 196hp might be a bit heavy in my opinion. I flew the regular 244hp eagle at 3200lbs before I switch to the screaming eagle, and it was a hog on ground roll and climb was alright. With the screaming eagle with 310hp, and at 3368, it climbs great, and it could handle a higher weight for sure.

[Tim Jodice]

1 hour ago, jlunseth said:

Why stop at 2900, why not 3200. My understanding, admittedly limited, is that the issue is the landing gear, and there have been several upgrades to 3200 by changing that, the Rocket Engineering modifications being just one example. Was the Encore not also an upgrade to 3200, or at least something over 3,000. 

How about in the middle of 3050. Random? Nope, that is the gross weight of a older Cirrus SR20 when it was powered by the 200HP Continental. 

[jlunseth]

I want 3200. Then I can fill the seats, put baggage in, fill the tanks, and not worry about weight.

I am already at 2900. 3050 would just allow me to get a little fatter, and my copilot to have a little more luggage. 

[Ragsf15e]

7 hours ago, Ron McBride said:

As a former owner of an F, in my humble opinion with a useful load of over 1000#’s.  I did not need another 160# useful load.  
would the airplane handle it, yes.    Add density altitude to it, it would be just so so.  I rejected one takeoff and spent the night in Gallup NM.  I was well below gross weight, approx. 450#’s below gross.  The next morning, 15* cooler the plane wanted to fly and we went.  
Most of my flying was in the western half of the country.  Home base was at 2250’ with mountains around and summer density altitudes of 5000’. 
Just an old conservative pilots opinion. 
 

 

At max gross weight of 2740, my F is fine up to DA of around 5,000’ for takeoff but then I really start paying attention to runway length and terrain.  During climb it’s ok at 2740 until around 10,000’, then its down to 200-500fpm.  It also cruises noticeably slower at max gross.  All of these factors start getting worse and harder to control when you add in thermals, turbulence, wind, etc which are common where I live.  

In my humble opinion, a gw increase for the F/J would reduce the safety factor too much and I wouldn’t do it.  If I had a turbo or TN, then I could see it.   It would probably still be safe at very low DAs, but I don’t think it would be a good idea for most of our operations.

Why doesn’t someone get the C/E up to 2740?  Basically it would be same as the F?

[Hank]

14 minutes ago, Ragsf15e said:

Why doesn’t someone get the C/E up to 2740?  Basically it would be same as the F?

Sounds good to me! An extra 165 lb would give me 822 lb full fuel payload!

[M016576]

6 hours ago, EricJ said:

I think if it were easy it would have been done the same time as the GW increase for the higher serial #s.   It's been identified here a few times that there is a difference in the steel cage, either the wall thickness of a particular bar or some other change.    It's definitely the sort of thing that can be done, but not just a paperwork change.    The weight of the rudder balance changes as well.

 

I’d agree with you if it wasn’t for the fact that rocket engineering upped the max gross weight on the old J’s and K’s to 3200 with no alterations to the steel cage at all, just a couple of low cost landing gear components.  So really it comes down to this: the factory has the test data for the later model J/K’s to 2900... and rocket engineering has the test data for 3200.  The factory isn’t/won’t/can’t use the rocket test data... and Rocket has no interest in producing the gross weight increase for a stock J/K, as their STC most likely exclusively considers their engine mount/power plant.  
 

I think of a third party DER took an analysis... or even just drew an inference based on the current 2900 and 3200 max gross weights, they could get a “STC kit” together for pretty cheap, and relatively easily.  I’m willing to bet each kit would cost the producer under $750 once all approved, said and done... and I bet they could sell that STC for $2500 and they’d move like hot cakes.

[M016576]

5 hours ago, bluehighwayflyer said:

I have always suspected that the 2900 pound gross weight increase was really little more than a paperwork shuffle and that the factory only made it retroactive a few serial numbers back in order to appease very recent new aircraft purchasers who would have otherwise probably been pretty perturbed at the timing of their purchases.  I suspect that they could have just as easily applied the gross weight increase at least to the entire F and J fleet if they had wanted to, but it was hard enough selling new 201s in the late 80s as it was. Who would have wanted to have only exacerbated that problem by creating a entire fleet of slightly used 201s with 200 plus pound higher useful loads than had new production due to the earlier birds’ substantially lower empty weights?  But, of course, I don’t know and am only speculating.  This would have made business sense at the time, but now, of course, is a different story.  

This is the same story I have heard regarding the 2900 limit.  And based on rocket engineering getting the stock old school J/K airframes up to 3200... that supports this argument.

[M016576]

5 hours ago, bluehighwayflyer said:

Are those tubes really the limiting factor and, if so, did Rocket Engineering upgrade them on early 201s when they went all the way up to 3200 pounds with their Missile mod?

These tubes *were not* modified with the missile mod.  I have the STC paperwork that describes what was done to up the gross weight to 3200... it’s a couple of new model K landing gear components.

My guess is the extra thickness on those tubes actually isn’t a required structural change at all... but instead some sort of supply line/manufacturing synergy.  Just a guess on my part.... but I do know for a fact that the missile and rocket mods *do not* have any changes done to the cage.

 

I should also mention that my aircraft is a 1982 J that was modified to a missile: it would not otherwise be eligible for the 2900lb stc, if it hadn’t been made a Missile (up to 3200)

Edited December 28, 2020 by M016576

[Ragsf15e]

32 minutes ago, M016576 said:

These tubes *were not* modified with the missile mod.  I have the STC paperwork that describes what was done to up the gross weight to 3200... it’s a couple of new model K landing gear components.

My guess is the extra thickness on those tubes actually isn’t a required structural change at all... but instead some sort of supply line/manufacturing synergy.  Just a guess on my part.... but I do know for a fact that the missile and rocket mods *do not* have any changes done to the cage.

 

I should also mention that my aircraft is a 1982 J that was modified to a missile: it would not otherwise be eligible for the 2900lb stc, if it hadn’t been made a Missile (up to 3200)

All you guys with more power, the higher max gross sounds reasonable to me from a performance/operation standpoint.

[PT20J]

None of this really matters: The point is that there is no way to get gross weight increases without either complying with the type certificate or an existing STC. 

If someone thinks it’s a great business proposition to get a new STC to up gross older airframes then I’m all for it. Thus far, Mooney hasn’t wanted to bite that apple, but someone else might make a different ROI calculation. You probably could not get data from Mooney or Rocket — I’m pretty certain that is closely held as proprietary. @Blue on Top might have some idea as to the process and cost to get the data package for FAA approval.

For me, it was just cheaper to buy the airplane that fit my mission.

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