Was I wrong? Refused to taxi or park on grass at Sun n Fun

[Mooney in Oz]

1 hour ago, Bob_Belville said:

If that's not acceptable I need to park at another field and commute or make a reservation and pay to park at the FBO.

I get your point Bob, but @FloridaMan may have decided to do that if negotiations had failed rather than attempt at what he saw as a real enough risk. Years ago when I visited Kerrville, for the first time I saw a 305 Rocket and the first thing I noticed was the low clearance between the downward prop blade and the ground, so I appreciate his concern as I would be if I owned one of those magnificent machines.

I'm very risk averse in my J when it comes to grass parking areas in that it has to look better than average and reasonably level as I won't risk not knowing what is under long grass on an uneven surface whether it is wet or dry. 

The point I'm trying to make is that as PIC, whether in the air or on the ground a judgement call is frequently required and in this instance, in my view the right judgement call was made as following sensible negotiation, the end result was no prop strike incident.

[Jim Peace]

1 hour ago, Bob_Belville said:

or make a reservation and pay to park at the FBO.  

side note:  if you are based at a sheltair anywhere else, parking is free at the FBO at SNF....

[Don Heene]

The usher says "park it here" prop strike "oh my bad sorry"  and you're out over 50 grand.  Tell him to sick it, you made a very good call. 

[Shadrach]

39 minutes ago, Mooney in Oz said:

I get your point Bob, but @FloridaMan may have decided to do that if negotiations had failed rather than attempt at what he saw as a real enough risk. Years ago when I visited Kerrville, for the first time I saw a 305 Rocket and the first thing I noticed was the low clearance between the downward prop blade and the ground, so I appreciate his concern as I would be if I owned one of those magnificent machines.

I'm very risk averse in my J when it comes to grass parking areas in that it has to look better than average and reasonably level as I won't risk not knowing what is under long grass on an uneven surface whether it is wet or dry. 

The point I'm trying to make is that as PIC, whether in the air or on the ground a judgement call is frequently required and in this instance, in my view the right judgement call was made as following sensible negotiation, the end result was no prop strike incident.

I thought the spec for all Mooneys was 9.5-10” of ground clearance. Does the rocket’s prop clearance differ?

[FloridaMan]

2 hours ago, Bob_Belville said:

There are limits. Try insisting that you get to park between the Blue Angels or in the P51 line.

Sun 'n Fun (and AirVenture) means parking on grass for the hundreds (thousands) of fly in planes. If that's not acceptable I need to park at another field and commute or make a reservation and pay to park at the FBO.  

That's a bit of a strawman argument there. 

I came back yesterday and flew the M20F and even that plane bounced along during the taxi. Other pilots approached as I was tying her down and mentioned how close the prop looked to the grass during the taxi, but I didn't see any grass stains on it. The empty weight of the Rocket is nearly 500lbs more than the F; while there's a second battery and slightly larger control surfaces in the back, I don't think it's necessary to calculate out the W&B to figure out that there's a lot more weight on the nose wheel. Pressure == Force/Area. Divide the weight of the airplane by the contact patch of the three wheels and then figure out how much is on that nosewheel contact patch based on WnB and I'd bet you're well within heavy twin territory (that ramp included 414s). Pressure is pressure. Try riding a road bike across a wet field or the beach. 

[gsxrpilot]

If you know you're going to an event like SnF or OSH, you have to know that parking is on the grass. It is a bit precious when other Rockets are parked on the grass, to think that yours can't. It's certainly within your right to not want to park on the grass. But then don't fly to an event where parking is on the grass. 

Mooney nose gear actually do better protecting their prop than some other types. Those pucks can only compress so much. So unless your nose wheel falls in a hole, or plows a trench deeper than the axel, there's no chance you'll touch the prop to the ground.

[FloridaMan]

43 minutes ago, Shadrach said:

I thought the spec for all Mooneys was 9.5-10” of ground clearance. Does the rocket’s prop clearance differ?

I have around 4" less prop clearance on the Rocket than I do on my M20F. I believe the Rocket has a 76.5" diameter prop and more weight on the nosewheel. Both planes have gear biscuits that are 3-4 years old. I can span my hand and touch the prop with my pinky and the ground with my thumb on the Rocket. 

[Mooney in Oz]

On 4/6/2019 at 10:56 AM, FloridaMan said:

It had rained all morning and was raining when I landed. I was told beforehand by two separate individuals to request "Heavy Aircraft Parking."

 

1 hour ago, gsxrpilot said:

It is a bit precious when other Rockets are parked on the grass, to think that yours can't.

Paul, I think that is a bit unfair when he was advised by two others to request heavy aircraft parking following the rain and probably for good reason.  The other Rockets may have or may not have arrived the previous day when perhaps it was or wasn't raining.  Regardless, it appears he made his decision based on advice received and his own observation, which to me was a good decision and one that I would have made.

[Marauder]

If you know you're going to an event like SnF or OSH, you have to know that parking is on the grass. It is a bit precious when other Rockets are parked on the grass, to think that yours can't. It's certainly within your right to not want to park on the grass. But then don't fly to an event where parking is on the grass. 
Mooney nose gear actually do better protecting their prop than some other types. Those pucks can only compress so much. So unless your nose wheel falls in a hole, or plows a trench deeper than the axel, there's no chance you'll touch the prop to the ground.

Hey! I have same concerns parking on grass. Same issue as Floridaman. I’m 500 pounds heavier than the average F. Care to guess why?

Well I’ll tell you!




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[Shadrach]

4 hours ago, FloridaMan said:

I have around 4" less prop clearance on the Rocket than I do on my M20F. I believe the Rocket has a 76.5" diameter prop and more weight on the nosewheel. Both planes have gear biscuits that are 3-4 years old. I can span my hand and touch the prop with my pinky and the ground with my thumb on the Rocket. 

Something is weird then. Both the F model and the 231/252 were delivered with 74” two bladed props. The Rocket has the 76.5” three bladed McCauley . 2.5 inches of extra diameter equals 1.25” of additional radius (extra length on each blade). If you have another 2.75” on top of that, I would be concerned about the nose gear rigging. The extra weight should not compress your nose gear that dramatically. 

 

 

Edited April 7, 2019 by Shadrach

[Jim Peace]

3 hours ago, gsxrpilot said:

If you know you're going to an event like SnF or OSH, you have to know that parking is on the grass.

I parked at the FBO no problem,.....

Plus the grass is full of uneven divots so to speak that even though my Johnson bar holder is in good shape I don't want to chance it....My plane would be totaled on the spot if it came loose and collapsed.....looking at belly damage and engine and prop work etc. A way to get back home and then doing remote mx....just find asphalt and life is good.

[Austintatious]

has anyone converted their prop to a 4 or 5 blade to get extra clearance?  There was a pretty cool 5 blade on display at SnF. for big bore engines.

 

 

Edited April 7, 2019 by Austintatious

[Bob_Belville]

2 minutes ago, Austintatious said:

has anyone converted their prop to a 4 or 5 blade to get extra clearance?  There was a pretty cool 5 blade on display at SnF. for big bore engines.

I don't know what the dia. of the 4 or 5 blade props are but, in spite of assumptions to the the contrary, the standard 3 blade props have the same dia. and ground clearance as the 2 blade. (FWIW, a 74" prop @2700 rpm has a tip speed of 872 fps. That's almost 0.8 mach.

[Bob_Belville]

To each his own, flying involves weighing various hazards. I had a taxiing prop strike in 2013 at 6B6. Paved tarmac, 50' from the fuel pumps. Stuff happens.

OTOH, I've been into AirVenture 3 times, SnF twice and I've made hundreds of grass landings with my (short coupled) Es. I was based at NC52 for several years. The first year at KOSH the nose gear tire went flat while taxiing in pretty heavy grass to the South Forty. No prop strike.  

[Guest]

I saw several Comanche 400's on the grass, 700 plus pound engine and prop combinations with no issues.  The joys of a Piper!!

Clarence

[Guest]

You're right, the nose wheel on a Commanche is indeed from a Mack truck, however the one installed on the Piper Comanche is made by Cleveland.

Clarence

[fantom]

Glad to note that Marauder is hanging with thinner women.  Used to be easy to park at the FBO and bu back and forth to the show. SnF made it much more difficult about 8 years ago. Be very careful when those volunteer marshals are guiding you taxiing. I saw one guide some unlucky pilot into clipping the nose of a Cezzna with his wingtip. 

The first year I flew into SnF, parked on grass, after some clueless marshal guided me on a long grass trip. It took me an hour to pull all the grass and weeds out of my main gear. 

Never again! Caveat Emptor.

PS: Jim. there ain't much else to do in the northern frozen tundra these days 

 

 

Edited April 7, 2019 by fantom

[FloridaMan]

[Bob_Belville]

Those inner gear doors - not as expensive but more at risk on grass. 

[PT20J]

I'm curious - we all know that the Mooney's sit low and the stiff gear makes the plane do a kind of scary hobby horse teetering when taxiing over rough surfaces (paved or not). But how many have actually had prop strikes taxiing off pavement? 

[xcrmckenna]

[/img]

Full feathered is sexy!!!!!!


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[Shadrach]

6 hours ago, FloridaMan said:

Beautiful machine but the pic does not tell much about prop clearance.

[carusoam]

Summarizing the best I can....

1) PIC rules! 

2) Planning in advance, doesn’t always work at the Marshal level.

3) Parking at the FBO is really hard to organize on the fly...

4) The most important thing to avoid is holes and steps...  often found getting on and off pavement...

5) Soft ground is mostly a challenge to taxi through...  friction grows exponentially... as you plow a lot of mud out of the way...

6) Soft ground issues increase... once you stop for more than a moment...  powering out of the hole. Is like taxiing over a wheel chock, without any momentum...

7) 280 horses couldn’t pull an O out of a Sloshkosh parking space... Amazing that a few people could push it....

8) Grass stains... My C got some back in the day... in the North 40... or VAC... parking one year...  it wasn’t known as a sign of ground strike at the time....

9) Big fear...  finding a deep hole that you can’t see...   watching the guy taxi in front of you gives a small hint what you are about to find....

10) +1 for Antares reporting what he saw, and sharing the decision process that went with that...

11) I get uncomfortable adding anything more than a small amount of power while taxiing... 

12) It isn’t easy going first, or having a heavier plane, or already having ground strike experience... even OH or prop replacement experience will make you think a lot!  It’s a long taxi to think about it... don’t rush.

13) it would take a large conspiracy to take up 9” of prop clearance... a deep hole, a tall step, compressed donuts, low air pressure, tall clumps of grass, an extra helping of momentum....  and Rob’s late entry... compressed engine mounts....

14) the fly-in organizers have a ton of responsibility... to make sure the grounds are ready for planes to roll on every inch of the space...  they must spend a lot of time and effort filling holes and smoothing lumps... even then... they are still not PIC.

PP thoughts only, ideas gathered on MS...

Best regards,

-a-

[takair]

Beyond condition of pucks and prop diameter, I would think the condition of the engine mounts are another variable.  I suspect that could be worth an inch of clearance in some cases.  If clearance seems too little, this would be another consideration.

We have a local airport (KBID) where grass parking is routine, but they always put Mooney’s on the pavement....without asking.  I suspect they have had a few problems over the years.  Tough call at the shows.  They are set up to move lots of traffic, so any disruption is not exactly viewed kindly.  

One area to watch out for is transitioning from grass to pavement.  I recall seeing a Glasair at one of the shows clip it’s prop while trying to get back on the pavement.  

[Danb]

Some of the above dialogue is interesting at best...Hell no you weren’t wrong protecting your  rocket..