300hp Missile Conversion of M20J - Pros and Cons

[Sixstring2k]

Does anyone know if rocket engineering is still around and supporting the rockets and missiles? Are there any new gotchas? 

[Lois]

I had my exhaust rebuilt about a year ago. Don’t bother trying to call. Just email and they will get back in touch with you. 

[Fly Boomer]

1 hour ago, Sixstring2k said:

Does anyone know if rocket engineering is still around and supporting the rockets and missiles? Are there any new gotchas? 

Darwin can be hard to reach, but they appear to be providing parts and service on Rocket Engineering parts.

[Missile 300]

5 hours ago, Sixstring2k said:

Does anyone know if rocket engineering is still around and supporting the rockets and missiles? Are there any new gotchas? 

I had an engine mount repaired by Rocket in Spokane a couple years ago.  They answer the phone occasionally.  email works better.

Online records shows that Darwin Conrad, founder/owner is 74 years old......so don't wait too long.

[Danb]

On 3/7/2024 at 2:01 PM, Jetpilot86 said:

When I was looking, as intriguing as the Rocket line was, longer term support was a concern I had so the more units of a model available in my mission parameters the better.

As a first time owner, after a long hiatus from GA making a living getting paid to fly jets instead, the fewer variables, the better for me.

Probably should have hopped back in GA 5-6 years ago, with a 182.  However, while the learning curve has been steep, many thanks to those here keeping it shallower, I'm really enjoying my Bravo. 

You should best Mooney made IMO

[Sixstring2k]

2 hours ago, Missile 300 said:

I had an engine mount repaired by Rocket in Spokane a couple years ago.  They answer the phone occasionally.  email works better.

Online records shows that Darwin Conrad, founder/owner is 74 years old......so don't wait too long.

So no one else can fix the engine mounts?

 

[Schllc]

3 hours ago, Danb said:

You should best Mooney made IMO

After close to 200 hours behind lycoming io540’s, it’s easy to see what you liked. 
I will forever love my acclaims and they are phenomenal planes, but I would love to see a Mooney with the io540-s1a5 and an acclaim cowling(not sure where to put the intercooler).  
I’m betting it would be faster than the continental, and it would be so much quieter at 2200rpm. 
 

[Missile 300]

58 minutes ago, Sixstring2k said:

So no one else can fix the engine mounts?

They have been repaired in the field and reported here on MS.  I don't recall anyone saying that they know of a shop that will do it. 

The Missile engine frame is made of 3 different types of tubulars with wall thickness that gets thinner the further out it goes. I think the Rocket is similar.  I assume they did it to save weight.  It does not take much corrosion to exceed 10% of the wall and render it non-airworthy.  At the first sign of corrosion get in there and spot treat/paint.  It happens where the tubulars are near the exhaust.

At Rocket, corroded tubulars are cut out and the replacement tubulars are filled with linseed oil in the welding process and the entire frame is all powder coated.  The field repair (see below) is different and is a patch with split sleeve splices .  Apparently Rocket shared drawings or specs with the owner and AP and signed off on the repair.  It ain't pretty but it worked. 

You asked about "Cons".  The Rocket and Missile engine frame designs result in a lot more time to remove and replace the engine than compared to an Ovation or Acclaim.  This post below said budget 80 shop hours to "R&R" the Rocket engine.  So if your shop is hitting you with $100-125/hr then just the cost of pulling the engine and reinstalling will be $8,000 - 10,000.  Others scoffed but I can tell you it took the same for the Missile.  The Missile has an eight (8) point engine mount - that is 8 mounts to buy and install.

 

[Sixstring2k]

3 hours ago, Missile 300 said:

They have been repaired in the field and reported here on MS.  I don't recall anyone saying that they know of a shop that will do it. 

The Missile engine frame is made of 3 different types of tubulars with wall thickness that gets thinner the further out it goes. I think the Rocket is similar.  I assume they did it to save weight.  It does not take much corrosion to exceed 10% of the wall and render it non-airworthy.  At the first sign of corrosion get in there and spot treat/paint.  It happens where the tubulars are near the exhaust.

At Rocket, corroded tubulars are cut out and the replacement tubulars are filled with linseed oil in the welding process and the entire frame is all powder coated.  The field repair (see below) is different and is a patch with split sleeve splices .  Apparently Rocket shared drawings or specs with the owner and AP and signed off on the repair.  It ain't pretty but it worked. 

You asked about "Cons".  The Rocket and Missile engine frame designs result in a lot more time to remove and replace the engine than compared to an Ovation or Acclaim.  This post below said budget 80 shop hours to "R&R" the Rocket engine.  So if your shop is hitting you with $100-125/hr then just the cost of pulling the engine and reinstalling will be $8,000 - 10,000.  Others scoffed but I can tell you it took the same for the Missile.  The Missile has an eight (8) point engine mount - that is 8 mounts to buy and install.

 

Thank you for the reply. 

[Fly Boomer]

5 hours ago, Missile 300 said:

The Missile has an eight (8) point engine mount - that is 8 mounts to buy and install.

The eight points are at the airframe end, not the engine end.  The engine has the usual four elastomeric mounting points.  The Rocket has four bolts in shear at the bottom of the truss, and four bolts in tension at the top and in the "middle".  The modifications on the airframe end are the reason the usual welding shops can't guarantee alignment and, even if a shop agreed to try a repair, they probably shouldn't be used -- they have no jig to align the airframe side of the truss.  The good news is that, for a price, Rocket will cut out the bad tubes, weld in new tubes, powder coat the mount, and return it in like-new condition.  And, if you should need it for some reason, they will even sell you a brand new mount.