Question, for the experimental guys, I'm considering installing 6" extended gear on my exp pacer w/ cub gear mod. I'm thinking I'll probably buy a set of legs from super-12, I am having a hard time finding the struts for the 6" gear mod. Do the 3" struts work for the 6" gear legs or have the guys running 6" been fabricating their own? any suggestions would be helpful thanks
6" extended gear
- Thread starter JBUZZ
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Thanks, cubunltd, what kind of steel did you use?
dakotacoyote
Registered User
Western SD
Any particular reason you want 6" extended gear? Have you ever landed a taildragger with a set?
No I haven't ran 6" gear before, other than the obvious reasons prop clearance and AOI I think it would help me be able to touchdown slower without hitting tail wheel first, but I think DW has a more logical idea, maybe ill just make my own gear all together where can you get ahold of the axles?
skywagon8a
MEMBER
SE Mass MA6
That is my question also. On a Pacer? I would think, without actually having done it, that 6" extended gear would hurt take off performance on a Pacer since the wing is short. The short wings do not have the higher aspect ratio of a Cub, which is where most of the low speed performance originates. The long gear on the Pacer would likely generate more low speed drag, thus retarding performance. If you have a BIG engine, perhaps the long gear would help? The extra power could overcome the extra drag.
nanook
MEMBER
northern alaska
You don't want to put the 6" gear on anything. Even Dodge admitted that after selling 6" gear for a few years. His comment to me was, "the geometry is wrong"..... He quit making and selling 6" gear... When people would try to order 6" gear from him, he would try to talk them out of it...
Gordon Misch
MEMBER
Toledo, Wa (KTDO)
He told me that too, when I inquired.
sierra bravo
Registered User
Atlee's only hesitation about 6" gear in my discussions was that he didn't own the STC. He told me to get the STC from Ron Sullivan and he'd build the gear, no problem. Whether he thought it was a good mod? A guy has to figure the Atlee factor into that discussion. Atlee didn't like Bushwheels. Thought they were unnecessary and that was at the time 31s were just coming out. What would he think of all the 35s? He was old school. He didn't see the evolution of Cub mods in the same light that others do. Especially mods that weren't his own. No big deal. I still enjoyed his presence.
Carey Gray
Registered User
Thun Field, Washington
If 3" is cool, isn't 6" cooler?
Some will say that it doesn't matter if it's cool or not, it's all about performance.
Those people aren't paying attention.:lol:
I saw a sticker on a motorcycle fender that said "It used to be about motorcycles, now it's a fashion show".
Some will say that it doesn't matter if it's cool or not, it's all about performance.
Those people aren't paying attention.:lol:
I saw a sticker on a motorcycle fender that said "It used to be about motorcycles, now it's a fashion show".
Carey Gray
Registered User
Thun Field, Washington
Anything that's worth doing is worth overdoing.:lol:
Dave Calkins
Registered User
Anchorage, Alaska
ha ha ha ha ha ha ha ha ha ha ha ha.
...lotsa opinions.
...any experience?
...I never did it on a Pacer.
..done it on a cub.............rockin' baby. Rockin!!!!
SBs words above about Atlee "factor" ring true
...lotsa opinions.
...any experience?
...I never did it on a Pacer.
..done it on a cub.............rockin' baby. Rockin!!!!
SBs words above about Atlee "factor" ring true
nanook
MEMBER
northern alaska
The 6" gear is tippy. I've had the unpleasant experience of flying for an operator that had a 180hp cub on 6" gear, put about 400hrs on it and it was unstable on uneven/soft ground.(tundra). The only other experience was in a J5 with a 0-290 in it. I only put about 12-15 hrs on that one. When I asked Atlee about the instability, he replied that the geometry was wrong. I don't buy the BS about not having the STC....he could have cared less... There are many thing wrong about making your gear longer and taller. But if you are just flying to airshows, who cares... If you are working the cub off airport with 6" gear. You are in for a rude awakening...
Dave Calkins
Registered User
Anchorage, Alaska
I respect Nanook's opinions on this site. However, I have not found this gear to feel "tippy". IT doesn't really "feel" different except that the nose is already up where you can fly the a/c on and off without "banging" the tail first or last!
My experience in this aircraft with 6" gear and 35's does not include tussocks of 2 foot rise and fall. Nanook, is that the kind of stuff you're on? You could be in for a rude awakening on ANY gear if you don't play it perfectly when the tussocks are huge.....you better have 35's too, right?
On skis, it is great gear. On 35's and soft ground, it is incredible!!!. The swampy stuff is doable now! SHHHH, Don't tell anyone
My experience in this aircraft with 6" gear and 35's does not include tussocks of 2 foot rise and fall. Nanook, is that the kind of stuff you're on? You could be in for a rude awakening on ANY gear if you don't play it perfectly when the tussocks are huge.....you better have 35's too, right?
On skis, it is great gear. On 35's and soft ground, it is incredible!!!. The swampy stuff is doable now! SHHHH, Don't tell anyone
Rob
Registered User
AZ06
I too respect Nanook's opinion, and this very topic has come up several times. Generally it goes inflammatory as the passions rise, and then dies out...
I have now ran out two engines and two rebuilds on the very same cub wearing 6" gear. I find that like anything else it has it's trade off's good & bad. But I have never quite understood the 'tippy' part. We all know the gear legs depart the fuselage in such a manner that they actually gain twice as much in width than they do in height, so by my feeble way of thinking, they are actually getting more stable as they gain in height. The seat of my pants confirm this for me.
FWIW, this cub is also on 35's, and our 'tussocks' are generally made of sage, but in all other respects, not much different than yours, Our rocks volcanic, but again, I don't think the gear cares about that?
I do understand why they got a bad rap on skis, but can't for the life of me understand it on wheels, if the good charecteristics out weigh the bad for a particular mission.
On the other hand maybe he what Nanook meant is fore and aft wise, as in tippy when you're up on the mains and more of a potential for a nose over? I could see the extended arm being a factor there, but have a hard time seeing that as a factor a person with much time and experience... I can say if bad luck, poor planning or just plane Murphy's law find you on the tail high side, it is a TON tougher to blow the tail back down...
Not meant as a dig, just trying to understand.
I have now ran out two engines and two rebuilds on the very same cub wearing 6" gear. I find that like anything else it has it's trade off's good & bad. But I have never quite understood the 'tippy' part. We all know the gear legs depart the fuselage in such a manner that they actually gain twice as much in width than they do in height, so by my feeble way of thinking, they are actually getting more stable as they gain in height. The seat of my pants confirm this for me.
FWIW, this cub is also on 35's, and our 'tussocks' are generally made of sage, but in all other respects, not much different than yours, Our rocks volcanic, but again, I don't think the gear cares about that?
I do understand why they got a bad rap on skis, but can't for the life of me understand it on wheels, if the good charecteristics out weigh the bad for a particular mission.
On the other hand maybe he what Nanook meant is fore and aft wise, as in tippy when you're up on the mains and more of a potential for a nose over? I could see the extended arm being a factor there, but have a hard time seeing that as a factor a person with much time and experience... I can say if bad luck, poor planning or just plane Murphy's law find you on the tail high side, it is a TON tougher to blow the tail back down...
Not meant as a dig, just trying to understand.
Just trying to understand too...I thought if the mains were extended up or forward moving the CG aft and it would make the tail heavier and harder to lift making that one of the disadvantages of it....or I could be wrong. Can anyone explain how /why this happens.
skywagon8a
MEMBER
SE Mass MA6
Make a side view drawing with the aprox CG located both horizontally and vertically. Level the drawing and note where the cg is located in relation to the axle. Next place the tail wheel on the "ground". Notice how far the cg moved aft. Now, lengthen the main gear and install larger tires and repeat. Notice how much further the cg moves aft. The tail wheel will show more weight, if it were on a scale. Thus the wing will need to generate more lift to raise the tail even though the empty weight of the plane may be the unchanged.
nanook
MEMBER
northern alaska
The cub that was tippy had extended wings with heavy drooped tips. The fuel tanks were the 30.5 dodge. Tires were early ABW 31" bias. The cub was tippy on the longitudinal axis. (side to side towards the wing tips) I didn't perform any maint on that cub. My dealings were strictly from a pilots perspective. I called A Dodge to see what his thoughts were on the problem. This was back in the mid 90's... The owner/maint pulled the 6" gear and replaced it with 3" gear and the problem went away. Obviously there is more to this problem than I can relate. I suspect they could have had too short of length lower shock struts installed.
The obvious problem with putting longer/taller gear legs on is, the stress on the gear attach points. You have not increased the strength of the attach points. You can't stick your head in the sand and pretend that you aren't over stressing that area. You have 35" tires on the end of a 6" extended gear. Just the stress of that tire surface area grabbing the ground when you slam on the brakes and then adding the leverage of the 6" gear extension. That is a huge increase of stress on the gear attach points. The rude awakening comes when something gives...
The obvious problem with putting longer/taller gear legs on is, the stress on the gear attach points. You have not increased the strength of the attach points. You can't stick your head in the sand and pretend that you aren't over stressing that area. You have 35" tires on the end of a 6" extended gear. Just the stress of that tire surface area grabbing the ground when you slam on the brakes and then adding the leverage of the 6" gear extension. That is a huge increase of stress on the gear attach points. The rude awakening comes when something gives...
Rob
Registered User
AZ06
I totally get the added arm and danger to the attach points. That is one of the 'trade offs' I mentioned.
My cub is a long winged cub, and used to have droops, although the wood tip rib, and booster tips have since been replaced by a stamped univair rib and light Dakota tips. Those alone took so much dead weight off the very end of the wing, that it made a huge difference in handling characteristics. This cub has stock tanks, an old -12 I used to fly had the 30.5's, and I can imagine how they would compound that handing...
One thing I have noticed with 6" gear and maybe this exasperated the tippiness feeling... Is that it eat's up bungees in half the time of 3" gear. And then you get the saggy bungee swaayyy. Not wanting to test my safety cables, I try to go through my bungees regularly, and I use 2 1280's all the way around. Here in the desert, where the temp. is already hitting triple digits, running 6" gear on bungees will put you on a first name basis with your bungee supplier.
But again, for my purposes the trade offs have mostly been warranted. I haven't flown it on 3" or stock gear since it's been on 35's, maybe that's where the happy medium is, if you want to run 35's.
As to the added tail weight increasing your ground roll,
I would say that is painting the horse with too broad a brush... Before we can make that assumption we have to qualify what's powering the beast, and what the wing is doing. I have no doubt that the added AOA going back and forth from (light weight) stock gear to 6" extended gear, more than trumps the added weight on the tail. But again, that's just my case, and obviously not going to be the case for everyone.
Take care, Rob
My cub is a long winged cub, and used to have droops, although the wood tip rib, and booster tips have since been replaced by a stamped univair rib and light Dakota tips. Those alone took so much dead weight off the very end of the wing, that it made a huge difference in handling characteristics. This cub has stock tanks, an old -12 I used to fly had the 30.5's, and I can imagine how they would compound that handing...
One thing I have noticed with 6" gear and maybe this exasperated the tippiness feeling... Is that it eat's up bungees in half the time of 3" gear. And then you get the saggy bungee swaayyy. Not wanting to test my safety cables, I try to go through my bungees regularly, and I use 2 1280's all the way around. Here in the desert, where the temp. is already hitting triple digits, running 6" gear on bungees will put you on a first name basis with your bungee supplier.
But again, for my purposes the trade offs have mostly been warranted. I haven't flown it on 3" or stock gear since it's been on 35's, maybe that's where the happy medium is, if you want to run 35's.
As to the added tail weight increasing your ground roll,
I would say that is painting the horse with too broad a brush... Before we can make that assumption we have to qualify what's powering the beast, and what the wing is doing. I have no doubt that the added AOA going back and forth from (light weight) stock gear to 6" extended gear, more than trumps the added weight on the tail. But again, that's just my case, and obviously not going to be the case for everyone.
Take care, Rob
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Sky,
Looks like I learned the last time you explained this...thanks again!!
I haven't built my gear yet so I can beef up the attach points to whatever is appropriate. I'm thinking of welding in a .090 plate vertically and on the floor of the front cluster where the gear attaches and a plate vertically on the rear attach cluster to reduce the flex in the longerons and help spread the forces generated by the longer gear.
I'm thinking 4" longer front gear leg that would be at 90* to the bottom longeron and a rear leg that would form the hypotenuse of the triangle but would still attach at the same angle as stock gear leg and weld in a step between the two legs to further strengthen the gear. I'm guessing that would add 3-4 pounds at the datum point so there would be little effect on CG from the added weight.
Does that make sense?
Looks like I learned the last time you explained this...thanks again!!
I haven't built my gear yet so I can beef up the attach points to whatever is appropriate. I'm thinking of welding in a .090 plate vertically and on the floor of the front cluster where the gear attaches and a plate vertically on the rear attach cluster to reduce the flex in the longerons and help spread the forces generated by the longer gear.
I'm thinking 4" longer front gear leg that would be at 90* to the bottom longeron and a rear leg that would form the hypotenuse of the triangle but would still attach at the same angle as stock gear leg and weld in a step between the two legs to further strengthen the gear. I'm guessing that would add 3-4 pounds at the datum point so there would be little effect on CG from the added weight.
Does that make sense?
skywagon8a
MEMBER
SE Mass MA6
You are guessing and then asking us if we think that your guess will be strong enough. Do you have any type of engineering background or do you know someone who does? I do not, but I do have a general idea of the direction in which the loads are directed and could probably figure out something that would be safe. I would first try to determine what would break first on the original gear. Then I would figure what the the new loads will be at those weak points on the new longer gear. Then I would adjust the weak points with enough more material so that the new landing gear will not be any more likely to fail than the original. It might mean a thicker piece of materiel or more edge distances. Or perhaps a different bolt? You really need to get into some mathematics to figure this out. There are books which have the strengths of materials that will tell you what sizes to use. That is the approach which I would take.
Dave Calkins
Registered User
Anchorage, Alaska
As to longer gear and overstressing gear fittings:
..I can not argue that a 6 inch longer lever isn't applying more force to the fuselage and fittings. It is.
...I CAN ask you to consider how much leverage a ski on a stock gear leg exerts on the gear leg itself.......and then how much force the SKI and STOCK LEG exert onto the longeron/fittings.
Apply the same logic.......to a stock leg and and one of ATLEE's tall ski pedestals.......talk about leverage!!?!!! and with no give like a nice, soft 35" bushwheel at 3.5 PSI!!
In a "....gear getting knocked off..." scenario...........gear gets knocked off. Period.
Long gear, short gear, if you hit the ditch or swale and it's deep enough, and your tires aren't soft enough or big enough, gear's coming off.
LOWrider........
.....the bird, she's a-gettin' heavier. But I can guess where you'd wanna gusset or add tubes to beef it up and add some more weight
.
Ken, thanks for the clarification on the big droops, extended wings, and Atlee tanks. The one I've been flying with the 6" gear and 35's is extended too...Stewarts tips....probably the lightest extended scheme available....the tip area is fabric with a small bow and a small rib right at the end.....ailerons out almost to the ends. Stock tanks, 1280 Bungees, mid-1100 pound Cub.
..I can not argue that a 6 inch longer lever isn't applying more force to the fuselage and fittings. It is.
...I CAN ask you to consider how much leverage a ski on a stock gear leg exerts on the gear leg itself.......and then how much force the SKI and STOCK LEG exert onto the longeron/fittings.
Apply the same logic.......to a stock leg and and one of ATLEE's tall ski pedestals.......talk about leverage!!?!!! and with no give like a nice, soft 35" bushwheel at 3.5 PSI!!
In a "....gear getting knocked off..." scenario...........gear gets knocked off. Period.
Long gear, short gear, if you hit the ditch or swale and it's deep enough, and your tires aren't soft enough or big enough, gear's coming off.
LOWrider........
.....the bird, she's a-gettin' heavier. But I can guess where you'd wanna gusset or add tubes to beef it up and add some more weight
.Ken, thanks for the clarification on the big droops, extended wings, and Atlee tanks. The one I've been flying with the 6" gear and 35's is extended too...Stewarts tips....probably the lightest extended scheme available....the tip area is fabric with a small bow and a small rib right at the end.....ailerons out almost to the ends. Stock tanks, 1280 Bungees, mid-1100 pound Cub.
Sky,
I dropped a career of being a civil engineer in my Jr. year...it was so boring that I couldn't imagine doing that for the rest of my life. So...not really but a bridge truss or landing gear..a little alike....if you designed for all possible variables then the plane would never fly. As Dave said, if you hit a big rock or ditch or the like doing 25 mph wearing 6.00x6, something on the plane is going to be broken. So far I have been able to outsmart those rocks and holes but I'm sure there is one waiting for me...out there somewhere.
Dave,
Wanta share your gusset guess?
I dropped a career of being a civil engineer in my Jr. year...it was so boring that I couldn't imagine doing that for the rest of my life. So...not really but a bridge truss or landing gear..a little alike....if you designed for all possible variables then the plane would never fly. As Dave said, if you hit a big rock or ditch or the like doing 25 mph wearing 6.00x6, something on the plane is going to be broken. So far I have been able to outsmart those rocks and holes but I'm sure there is one waiting for me...out there somewhere.
Dave,
Wanta share your gusset guess?
Dave Calkins
Registered User
Anchorage, Alaska
Spread the load.
Also, take care to ensure one of the members does not "attract" a load that the rest should be sharing.
All I could really say is 'build it like a Cub'. .........
Talk to Barrows if he'll talk to you about it.
I wanna see that wing, to be honest. Very interesting.
Also, take care to ensure one of the members does not "attract" a load that the rest should be sharing.
All I could really say is 'build it like a Cub'. .........
Talk to Barrows if he'll talk to you about it.
I wanna see that wing, to be honest. Very interesting.
