Jmodel 2blade vs 3blade gnd clearance?

[maniago]

I don't want to start a grass strip vs tarmac discussion, though I'm asking this question because I'll be flying in/out of a "pretty nice" grass strip. 

Is there much clearance diffence between a 2 and 3 blade prop?  Is it enough to seek out a 3 blade plane for purchase?  I know this is a J and newer page, but what about the older Cs & Es?  I can post on that page also, but trying here first to keep the info under one thread, and since there might be more "had one of those before" pilots here.  Thanks M

[fantom]

Actually "search" in the upper right hand corner will be a treasure trove for you.

We've mowed this grass before ;-)

[jlunseth]

From memory, I think it is two inches, but I would not buy a three blade on a J.  Too many comments from owners about vibration, and the three blade may help with climbout, but is slower in cruise by a few knots.  On the other hand, I have never tried one, I am just going from what I have read from other owners.

I have landed my 231 on grass and there is plenty of prop clearance with the two blade if your technique is half decent.  There is enough even if it is not very good.  I have flown into probably 20 different grass strips and none of them threatened the prop. 

[maniago]

ack!  I ran the search before I posted and got zippy, which I thought was odd, but I did it twice and twice the zippy.  Go figure.  Thanks

[Hank]

The vintage machines use the same diameter prop regardless of blade count. I verified on my C model during annual, when the spinner was off. [it's really difficult to measure the diameter of a 3-blade prop using a tape measure with the spinner in place.]

For what it's worth, I visit several nice grass strips semi-regularly, and I know other vintage owners who are based at grass strips. I would be leery of taking a long-body, or a converted mid-body with a heavy engine, onto grass, though. Short body, F, G, J should not be a problem. Talk to Parker about K's . . .

[maniago]

Quote: jlunseth

From memory, I think it is two inches, but I would not buy a three blade on a J.  Too many comments from owners about vibration, and the three blade may help with climbout, but is slower in cruise by a few knots.  On the other hand, I have never tried one, I am just going from what I have read from other owners.

I have landed my 231 on grass and there is plenty of prop clearance with the two blade if your technique is half decent.  There is enough even if it is not very good.  I have flown into probably 20 different grass strips and none of them threatened the prop. 

[maniago]

Quote: Hank

The vintage machines use the same diameter prop regardless of blade count. I verified on my C model during annual, when the spinner was off. [it's really difficult to measure the diameter of a 3-blade prop using a tape measure with the spinner in place.]

For what it's worth, I visit several nice grass strips semi-regularly, and I know other vintage owners who are based at grass strips. I would be leery of taking a long-body, or a converted mid-body with a heavy engine, onto grass, though. Short body, F, G, J should not be a problem. Talk to Parker about K's . . .

[rbridges]

oh yeah, with the seat scoot back for a taller pilot, the leg room in the back of a C or E is comical.

 

[Hank]

The back seat of a C/E is tight, but I don't ever sit there . . . Will you??   

The close grass strip that I visit most often is 2000' long with a slight bend, and a hump near the middle; both indicate the preferred landing direction, wind permitting, is upriver [02]; when departing downriver [20], stay to the right to avoid 55-60 mph temporary airborne condition just as the runway curves slightly to follow the riverbank. A straight departure is still possible when you get airborne the second time, but you will miss the slot in the trees and that can be exciting. I think I grayed some hair the day I forgot about the hump.

Four adults is possible if two really like each other. I took my wife's cousins flying once:  me, him, his college son, and son's college buddy. Weight restricted me to 34 gallons [out of 52], still good for 3 hours plus reserve. My seat is ALWAYS in the middle spot, back-seaters just have to adjust; I can drive crammed under the steering wheel, but will not fly crammed under the yoke. Their choice is cram in or don't go, safe operations will not be compromised.

Yes, we 4 guys started and ended our trip from a no-fuel grass strip, but it was 3500' long and 40' msl, covered in nice Carolina centipede grass. The fuel stops going each way were paved, and I dipped the tanks before, during and after fueling to ensure 17 gallons per side.

Ground clearance is not the issue with the short bodies, and unless going out with 4 adults, weight is rarely an issue. VOLUME is an issue [cubic feet, not sound level], the cargo area and back seat typically fill up with weight to spare, especially when traveling during the holidays with gifts, food, etc.

[Hank]

Two quick notes:  1) pushing the plane around on grass is difficult; 2) with the 3-blade positioned to allow towbar access to the front wheel, there is a LOT of clearance [knee high or more].

[maniago]

Quote: rbridges

oh yeah, with the seat scoot back for a taller pilot, the leg room in the back of a C or E is comical.

 

[maniago]

Quote: Hank

Two quick notes:  1) pushing the plane around on grass is difficult; 2) with the 3-blade positioned to allow towbar access to the front wheel, there is a LOT of clearance [knee high or more].

[fantom]

Quick search, for your perusal. It's all there. Good luck.

http://www.mooneyspace.com/index.cfm?mainaction=posts&forumid=3&threadid=3315

http://www.mooneyspace.com/index.cfm?mainaction=posts&forumid=4&threadid=1911

http://www.mooneyspace.com/index.cfm?mainaction=posts&forumid=1&threadid=3414

 

[xftrplt]

Quote: Hank

The vintage machines use the same diameter prop regardless of blade count. I verified on my C model during annual, when the spinner was off. [it's really difficult to measure the diameter of a 3-blade prop using a tape measure with the spinner in place.]

[rbridges]

Quote: maniago

We're short people in my family.  I'm 5'8, wife 5'7, my folks (getting) smaller  haha.  Kids, damn kids, are 5'10.  So if I'm in the upper left, who can fit in the rear left?  And a 5'10 kid in the upper right, who in the back right, so to speak?  Again, if its airline style ala American or Delta back of the bus-class or better, then its all GTG by my standards.  Comments?

[KSMooniac]

The previous threads have the answer, but I'll repeat just for the archives.... the MT prop is the only approved 3-blade prop for a Mooney with a smaller diameter.

[Hank]

Quote: xftrplt

Why is it difficult?.  Isn't the diameter, i.e., the swept disk (which is what's important) of any prop, with any number of blades, simply twice the radius of any one blade?

 

 

[fantom]

Quote: Hank

[Hank]

Hi, Gary!

Whatever you do, don't tell Piperpainter to stay on ashphalt, I don't think he ever lands on any . . . . .

[xftrplt]

F-Troop, I wanted an accurate measurement to confirm the same diameter shown for the 2-blade. That's twice the blade length plus the diameter of the spinner, which is hard to measure with a tape. With the spinner off, I can measure blade length to the root, then the length of each hub portion, add it all up, double it and add the diameter of the small piece in the center.

So, with a notional 12" spinner you get an hypotenuse 2" longer than the actual radius.

But, if you measure instead to the base of the spinner, 90 degrees from the blade, and assume an 8" diameter spinner, the difference is only 0.22", which I would think is accurate enough--especially for an engineer. 

F-Troop

[Hank]

I've learned about assuming the hard way, thank you very much!

The spinner measures ~14" on the hangar floor, but it has to be opened up slightly to mount it. Results look like this.

 

[MARZ]

Quote: xftrplt

Why is it difficult?.  Isn't the diameter, i.e., the swept disk (which is what's important) of any prop, with any number of blades, simply twice the radius of any one blade?

[jetdriven]

It is simple.  The 3-blade, except for the MT, has the same diameter.  That is it.  This horse has been beate to death and hung to dry into horse jerkty.

[maniago]

Not trying to be sassy, but if this has been beaten to death numerous times, the fact that it keeps coming up means it need to be a STICKY!  

Or better yet, put in a FAQ file with other kinds of often asked questions....hmmm?

BTW, never had horse jerky.  Is it any good?

[rbridges]

a FAQ section with references to LOP/ROP, 2 blade/3blade and reseal/bladders and links to good threads would be helpful.  anyway, didn't mean to derail the original thread.