Hot Starting a Mooney Rocket

[lrsi5774]

I purchased a Rocket about 6 months ago.  150SMOH so the engine is good and mag's are strong.

When I cold start, it fires up like a champ.

However, I cannot figure out how to best do a hot start.

Does anyone know any tricks out there?

 

 

[David Mazer]

The first day I had my Rocket I spent 45 min starting it after I added fuel. I finally called an A&P for advice which didn't really help.  I feel your pain.  I have been using this technique and it has worked for me pretty well.  Prop full forward, mixture full forward, throttle full forward, prime 3 seconds, half throttle, engage starter and be ready to retard the throttle when it kicks in (which takes a little longer than you would expect so let it go a little longer than normal).  Viola, engine on!

Welcome to Rocket land.

[aviatoreb]

Quote: lrsi5774

I purchased a Rocket about 6 months ago.  150SMOH so the engine is good and mag's are strong.

When I cold start, it fires up like a champ.

However, I cannot figure out how to best do a hot start.

Does anyone know any tricks out there?

 

 

[David Mazer]

Erik,

This may be a silly question but if you run the low boost for 60 sec, why doesn't that flood the engine?

This - mixture forward, prop forward, mixture cracked - is a flood start procedure.  I have had very little luck using it for hot starts.

[aviatoreb]

Quote: Mazerbase

Erik,

This may be a silly question but if you run the low boost for 60 sec, why doesn't that flood the engine?

This - mixture forward, prop forward, mixture cracked - is a flood start procedure.  I have had very little luck using it for hot starts.

[David Mazer]

I will have to try this.  Thanks for the useful and complete reference.

Without trying to start an argument on this forum, I think us Rocket flyers try to use the scientific method a little more than some of our brethren.  Well, maybe a better way to say that is a higher percentage of us.  Clearly a lot of the others on this forum are very well educated and trained on the subject but there are a fair share of rather loose opinions thrown around.  Or so it seems to me the casual, and biased, Rocketeer.

[aviatoreb]

Quote: Mazerbase

I will have to try this.  Thanks for the useful and complete reference.

Without trying to start an argument on this forum, I think us Rocket flyers try to use the scientific method a little more than some of our brethren.  Well, maybe a better way to say that is a higher percentage of us.  Clearly a lot of the others on this forum are very well educated and trained on the subject but there are a fair share of rather loose opinions thrown around.  Or so it seems to me the casual, and biased, Rocketeer.

[Chessieretriever]

I have a 351 Rocket and had the same problem until I adopted the following proceedure:

1. 
   
2. Prop full foward
   
3. Mixture completely out (cut out)
   
4. Throttle full forward
   
5. Prime for about 30 seconds
   
6. Stop prime and put mixture full rich
   
7. throttle back to idle
   
8. Prime for 1 to 2 seconds
   
9. Throttle to slightly more than idle (like 1/4 inch)
   
10. Start Engine
    

The priming with the mixture out is to purge the vapor from the hot fuel lines.

Hope this helps

[jetdriven]

If the mixture is at ICO then you are not priming the engine, you are circulating cool fuel through the fuel system under the cowling. 

I saw some CAP pilots in a 172SP forget and leave the mixture at full rich, and ran the boost pump for 30 seconds while reading each item in the checklist (they were not familiar with FI engines). They are big on procedures there.    Not a problem in a carbureted 172. Fuel was pouring out the cowling. They hit the starter and it caught on fire.  3 guys in green nomex flight suits running away.  One black outline of a burned up 172 on the concrete.

[aviatoreb]

Quote: jetdriven

If the mixture is at ICO then you are not priming the engine, you are circulating cool fuel through the fuel system under the cowling. 

I saw some CAP pilots in a 172SP forget and leave the mixture at full rich, and ran the boost pump for 30 seconds while reading each item in the checklist (they were not familiar with FI engines). They are big on procedures there.    Not a problem in a carbureted 172. Fuel was pouring out the cowling. They hit the starter and it caught on fire.  3 guys in green nomex flight suits running away.  One black outline of a burned up 172 on the concrete.

[David Mazer]

Quote: Chessieretriever

I have a 351 Rocket and had the same problem until I adopted the following proceedure:

[David Mazer]

Quote: aviatoreb

[aviatoreb]

Quote: Mazerbase

 So what's a 351 Rocket?

[David Mazer]

Quote: JimR

[aviatoreb]

Quote: Mazerbase

Yes, Chessier.  Please do.  Utilizing the rigorous scientific method that we have apparently come to expect of the Rocket community, of course.   

[aviatoreb]

Quote: JimR

All in fun, guys.  All in fun.  You know you're going to get a few swings when you pitch out softballs like that. 

Jim (who would love to own a Missile some day, and would even consider the mod to my current 201 if it was still available)

[rainman]

Is Deakins saying that this will work on all 6 cylinder Continental engines? I have a 231 and would like to try this technique for hot starts if applicable. I usually fuel away from home base and need to start it right up to get home.

Ray

[triple8s]

Some useful load on that liquid rocket!

[aviatoreb]

Quote: rainman

Is Deakins saying that this will work on all 6 cylinder Continental engines? I have a 231 and would like to try this technique for hot starts if applicable. I usually fuel away from home base and need to start it right up to get home.

Ray

[Chessieretriever]

For those that wanted to know more about the 351, it is a converion done by Darwin of Rocket Engineering using the TCM TSIOL-550A Voyager engine (single turbo) which is the liquid cooled version of that TCM engine. The engine is orininally rated for 350HP continous at 2700RPM and in the Rocket it is "detuned" to 335HP by limiting RPM to 2600RPM. Our airplane is based on a TLS and has additional gussets on the steel frame and the flight surfaces. Our plane was actually used for the FAA certification process and has been flown to FL350 by Rocket during that process (so they tell me anyway). It loves to fly as high as you take it and really shines up there.

Advantages are no cooling problems whatsoever (especially in the flight levels), very good critical altitude which makes for a quick climb into the higher FL's and (for me) the ability to fly LOP for cruise even as high as ~74% of the Mooney rating which is about ~70% of the factory HP rating. This translates into cruise speeds of ~220kts TAS at about 16.3gph and speeds of ~207kts TAS at ~15gph. Range is 1200nm+ in calm conditions and for max speed on ours at FL250 was 251kts (after a lot of work on the rigging and cleaning up the airframe itself). Obviously nobody (should) flys them firewalled. Disadvantages are ~100lbs of weight penalty which reduces useful load on the plane and if you fly it ROP it will use about 21gph. It has enough power to lift it's full gross at just about any airport in the US (including Telluride) at 1800ftm any time even when hot. Additionally it requires some special knowledge from your AP tech to maintain the watercooled system (a non issue for us as we work with Weber and they like N9154W)

[David Mazer]

Thanks for the information.  Sounds like an excellent traveling machine.

[aviatoreb]

Quote: Chessieretriever

For those that wanted to know more about the 351, it is a converion done by Darwin of Rocket Engineering using the TCM TSIOL-550A Voyager engine (single turbo) which is the liquid cooled version of that TCM engine. The engine is orininally rated for 350HP continous at 2700RPM and in the Rocket it is "detuned" to 335HP by limiting RPM to 2600RPM. Our airplane is based on a TLS and has additional gussets on the steel frame and the flight surfaces. Our plane was actually used for the FAA certification process and has been flown to FL350 by Rocket during that process (so they tell me anyway). It loves to fly as high as you take it and really shines up there.

Advantages are no cooling problems whatsoever (especially in the flight levels), very good critical altitude which makes for a quick climb into the higher FL's and (for me) the ability to fly LOP for cruise even as high as ~74% of the Mooney rating which is about ~70% of the factory HP rating. This translates into cruise speeds of ~220kts TAS at about 16.3gph and speeds of ~207kts TAS at ~15gph. Range is 1200nm+ in calm conditions and for max speed on ours at FL250 was 251kts (after a lot of work on the rigging and cleaning up the airframe itself). Obviously nobody (should) flys them firewalled. Disadvantages are ~100lbs of weight penalty which reduces useful load on the plane and if you fly it ROP it will use about 21gph. It has enough power to lift it's full gross at just about any airport in the US (including Telluride) at 1800ftm any time even when hot. Additionally it requires some special knowledge from your AP tech to maintain the watercooled system (a non issue for us as we work with Weber and they like N9154W)

[David Mazer]

Simply leave the mixture in full lean ("idle cutoff"), and run the electric boost for one full minute. Sixty seconds. Time it, by the clock. More won't hurt a bit, but less may well not be enough. A full 60 seconds, not a second less. The first few times you do it, it will seem interminable, but there's no reason you have to just sit there. When you know you're going to use this procedure, flip the pump on early, hit the stopwatch, and go ahead and do your cockpit setup, or study the instrument departure, or brief your passengers (you DO brief passengers, don't you?)

This little trick uses the ELECTRIC pump to pressurize the lines to the engine pump and the chamber inside the pump case itself. Since that fuel can't go beyond the fuel control with the mixture shut off, the only way out is through the rather small "vapor vent return" line. This is the exact purpose for which this line is provided.

Once this "cooling" step is done, the start is identical to the cold start, and just as easy. At the end of the sixty seconds, let the electric pump continue to run while you push the mixture in until the fuel flow stabilizes (as for the cold start), flip the boost off, and hit the starter. Instant gratification. Well, sixty-second gratification, anyway. In effect, this procedure converts a hot start into a cold start. (Actually, it may be better than a cold start, because the engine is warm, and the fuel will vaporize better.)

[aviatoreb]

Quote: Mazerbase

So I finally had a chance to try this out and it worked great.  I warmed up the engine, shut it down, full lean, low boost on.  I watched the TIT temerature drop from mid 800s to low 600s over the 60 seconds.  Instead of leaving the boost pump on I used the prime but, other than that, I used the above procedure.  I recommend it.  Thanks Erik.

[BobAustin]

Will this procedure work on a Missile (IO 550) that only has a high boost not low boost?

In the past I used this with my Cessna 340 with uses the same tsio520 that the Rocket uses...worked fine. 

Bob