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Taxing around without any cowling installed


tigers2007

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Is this acceptable practice? I’m fixing on removing all of the cowling and then taxing it around my hangar building to the other side to my A&P’s hangar - about 100 yds of travel. I’m concerned that maybe the cowling has some sort of structural function.

 

 

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Is this acceptable practice? I’m fixing on removing all of the cowling and then taxing it around my hangar building to the other side to my A&P’s hangar - about 100 yds of travel. I’m concerned that maybe the cowling has some sort of structural function.
 
 
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Have at er. Sometimes its necessary to ground run and leak check engines at other locations in an airport depending on its setup. You’ll see planes moving without the cowl on. Just stay out of the puddles and gravel.


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1 minute ago, steingar said:

Is there some reason the aircraft can't be towed that distance?  I'd be leery of firing up an aircraft engine in an enclosed space for a plethora of reasons.

What enclosed space? I don't think he is planning to taxi out of the hangar. I envisioned pulling the plane out, starting it and taxing between hangars, on pavement, to the maintenance shop a few hangars down and around the other side.

I've ground-run mine before during / after maintenance, but haven't taxied with the cowling removed. Thena gain, I don't remove the bottom cowl very often, either [maybe that's why I don't taxi . . . ].

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Has anyone ever compared the difference in the variance in rising temps between a cowled engine and one that’s not? I haven’t, but I’m just curious.   I could be totally wrong, but I would wager that a slow moving aircraft, with the cowling in place,  (one that’s taxiing for example) that the temps rise at a faster rate than one without the cowling.  For example, many radials are basically exposed and it’s no cause to panic when you see one taxiing by. 

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Personally, I would have no problem taxing my aircraft or customer aircraft with the cowl off , but I feel I am pretty careful. Air flow is a concern,  but a few mins of taxing won’t hurt anything. I would be careful of the oil cooler arrangement, any loose scat hoses, and make sure everything is secure. If you are asking, how to do this I wouldn’t advise it. 

I had a friend of mine taxi an Extra with out the cowl, he had a scat tube that was disconnected. That same hose clamp still attached to the scat hose poked a nice hole thru a $15k propeller once the hose blew around a bit. Yes it was launched forward into the prop.

I personally taxied a 2 seat Pitts for a run up with out the canopy once. The front belts were loose. One of the shoulder harnesses was blown from the front seat, almost knocked me out and broke an instrument. 

S$@T happens!

-Matt

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I think you guys are over thinking this.  Engines are run in test cells every day without an engine cowl.
Clarence


Agree, this should be no big deal. Taxi at low power and the temps should be just fine.


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I’ll be pulling it out by hand and then using the fan to move it around the building. I’ll make sure there aren’t any loose parts.

I also always wondered if it was appropriate to “power” the plane directly out of the hangar - I guess it isn’t acceptable practice...


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2 hours ago, tigers2007 said:


I also always wondered if it was appropriate to “power” the plane directly out of the hangar - I guess it isn’t acceptable practice...
 

Stop a minute and think:  when the prop goes round and round, the plane goes forward because the prop pushes a lot of air backwards. A lot of air, very quickly. What would happen in your hangar if you pointed God's own leaf blower in the door? Anything laying around? Papers, maps, boxes, rags, funnels on a shelf, small containers, a hat or two, cups, water bottles . . . . You get the idea. To say nothing of the noise the engine reverbrating inside a large metal box would make. Hope your hangar neighbors aren't there when you do this . . .

Edited by Hank
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I have seen banner tow planes operating without cowlings in flight to help with cooling in the high power, slow flight regime they operate in.  For at least those planes, the engine operated cooler when fully exposed instead of partially shrouded.  I was told they had an STC or similar in order to fly that way legally.  Those were Cubs or Cub knockoffs, not Mooney's where cooling is about ducting instead of exposed jugs in the air.  

Just PP observations at the field one day, YMMV...

-dan

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Depends on the model and location of the air filter.  I wouldn’t want to run very much without a filter.  Cowl meh.  You’re not running at High settings so go for it.  I’ve done it probably 50x with my J with no ill effect.   

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Nothing more than an idle. Imagine holding a fine toothed comb under running water. The water will not pass between the teeth and needs to be ducted. Engine cooling is like that. And, to add to that, once the air gets between those hot fins, it expands and creates even more resistance. 

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11 minutes ago, Antares said:

Nothing more than an idle. Imagine holding a fine toothed comb under running water. The water will not pass between the teeth and needs to be ducted. Engine cooling is like that. And, to add to that, once the air gets between those hot fins, it expands and creates even more resistance. 

I think this is true at higher than taci speeds. Cruise speeds maybe. I don’t see how at next to idle power in taxi uncowled can be bad for cooling. On the contrary I think having the cylinders exposed to  unrestricted ambient air would enhance cooling. 

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Somebody asked the same question recently, but this time it was for the TSIO540 in the Bravo....

There was a list of things that were no longer connected that would need to be tied down...

 

I would be in the camp of getting a good leg work-out in...

Mostly because I would get really agrivated if I missed some detail that would take even more time to recover from...

 

Would be a great time to test one of those fancy towbars...

 

Summary...

  • No strong reasons why this technically shouldn’t be done...
  • cooling for 100yd taxi isn’t that good anyways...
  • be aware that if the filter is not connected, some dirt is able to be sucked into the engine...
  • low power and low rpm generate low heat...
  • This operation surely shows how nice checklists really are...
  • There is no checklist to follow on this...
  • Mechanics and test runs and open cowling are done quite often...
  • keep an eye on your engine monitor... and both eyes out the windows... at the same time...
  • If leaving the doghouse in place, the cooling issues don’t change very much from normal...
  • If your mechanic is at the other end of the 100yd taxi... have him review what you are about to do... before you do it...

PP thoughts from what I think I just read...

Best regards,

-a-

 

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I don't think there's much of anything on a D model to leave unconnected, except possibly the air filter and landing light, and then only if he removes the lower cowl. If the lower cowl is removed, check everything and make sure that nothing can reach the prop. I was quite surprised to read above that loose engine bits can get sucked forward through the prop while it's busy pushing air backwards . . .

But I have also had no problem running up my C outside with the upper cowl and both cheeks removed. Won't swear whether we had reassembled the doghouse first or not; I'm guessing we did because it would have been uncomfortably hot leaning over the engine doing afterwards, and I'd remember that. 

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On 5/12/2018 at 7:04 AM, carusoam said:

Somebody asked the same question recently, but this time it was for the TSIO540 in the Bravo....

There was a list of things that were no longer connected that would need to be tied down...

 

I would be in the camp of getting a good leg work-out in...

Mostly because I would get really agrivated if I missed some detail that would take even more time to recover from...

 

Would be a great time to test one of those fancy towbars...

 

Summary...

  • No strong reasons why this technically shouldn’t be done...
  • cooling for 100yd taxi isn’t that good anyways...
  • be aware that if the filter is not connected, some dirt is able to be sucked into the engine...
  • low power and low rpm generate low heat...
  • This operation surely shows how nice checklists really are...
  • There is no checklist to follow on this...
  • Mechanics and test runs and open cowling are done quite often...
  • keep an eye on your engine monitor... and both eyes out the windows... at the same time...
  • If leaving the doghouse in place, the cooling issues don’t change very much from normal...
  • If your mechanic is at the other end of the 100yd taxi... have him review what you are about to do... before you do it...

PP thoughts from what I think I just read...

Best regards,

-a-

 

Bravo is tough if both upper and lower cowls removed...leaving scat attached ncaa intercooler scoop w/duct unsupported,ft air filter intake scoop flopping arround...both are large and difficult to safety...total removal leaves Turbo intake completely open...

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