VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > Main > RV General Discussion/News
Register FAQ Members List Calendar Today's Posts

Reply
 
Thread Tools Search this Thread Display Modes
  #221  
Old 01-13-2011, 06:14 AM
Jack Tyler Jack Tyler is offline
 
Join Date: Dec 2010
Location: Jacksonville, FL
Posts: 219
Default

Bob, what you see and describe is what I see - and especially the landing. The 'bounce back' of the nose gear after initial runway contact seems to me to be quite evident. And that uphill grade at the roll-out, mid-field point doesn't help, either. This reminded me of landings I've made, in a free-castering nose wheel AA-5, about which I was not very proud.

Jack

Last edited by Jack Tyler : 01-13-2011 at 06:14 AM. Reason: Lousy typing...
Reply With Quote
  #222  
Old 01-13-2011, 09:15 AM
Fred.Stucklen's Avatar
Fred.Stucklen Fred.Stucklen is offline
 
Join Date: Oct 2006
Location: Brooksville, FL
Posts: 356
Default Nose Gear Techniques

Quote:
Originally Posted by Captain Avgas View Post
Doug, you must have much better eyes and equipment than me. And I admire your willingness to defend a friend.

However what I see is the aircraft accelerate on take-off and the nose gear is firmly planted until rotation (typical spam can take-off).

On landing I see the nose gear positively contact the runway less than 1 second after the mains which indicates a very flat landing (typical spam can landing).

I'll have to take your word for it that there may be some sliver of daylight under the tire for some period after the first nose wheel contact but I'd be quite comfortable in saying that Mike Seager would not regard this take-off or landing as an illustration of best RV(A) practice in virtually nil wind conditions. Others may form their own opinion.
I've provided a fair amount of transition training to guys getting ready to fly their own creations. All have been done it in RV-XA models. The one thing I stress is that the top of the cowl should be parallel with the runway on take-off AND landing.
On take-off hold aft elevator until the the nose raises, and stop the rising movement at the point the cowl is parallel with the runway. The rest of the takeoff roll is like any other aircraft.
On landing, the approach speed is set such that the cowl top is level (slight up nose attitude) and held there until touchdown (using the throttle to adjust rate of descent, especially near the ground just before touch-down). The constant pitch attitude sets the approach speed. The pitch is the landing attitude. The pitch is maintained on the ground until the elevator runs ut of authority.
I've got 3383 Hrs in RV-XA aircraft. I did break a nose gear once due to a defect in the shaft near the motor mount (where it broke - old style landing gear), but, IMHO, due to proper technique, I haven't bent a nose gear under. I do not land on grass strips unless I am VERY familar with the condition of the field. If it's at all questionable, I won't land there.
The nose gear leg is KNOWN to be the weakest link in the landing gear. Respect it and it will serve you well. Abuse it, and it's not a matter of IF, but WHEN it will fail....
__________________
Fred Stucklen
wstucklen1@cox.net
RV-7A N924RV Flying (1825 Hrs & counting)
RV-6A N926RV 875 Hrs (Sold)
RV-6A N925RV 2008 Hrs (Sold)
Reply With Quote
  #223  
Old 01-13-2011, 09:31 AM
Andy Hill's Avatar
Andy Hill Andy Hill is offline
 
Join Date: Dec 2005
Posts: 976
Default

See RVator p3 for what Vans considers the (nosedragger) "landing attitude"

Read on a bit
Quote:
LANDING/TOUCHDOWN
I find it difficult to imagine how anyone can consistently land safely without a mastery of low speed control. While this point may be argued, the traditional landing objective is that of contacting the ground at or near minimum air speed. (A survey in the October 2010 issue of Sport Aviation showed a 52/48 percent preference for wheel landings over three-point landing. This would contradict my above statement of the ?accepted? preferred landing technique. It could mean that while the textbook dictate is the 3-point landing, user preference is a higher touch down speed ?wheel? landing. If so, one explanation could be that most pilots prefer the wheel landing because it is smoother for them, or it could mean that they lack the skills or confidence to do 3-point landings. I?ll discuss this in a future article.
and oh dear, he's going to have a go at the following RV-8 in the video as well for doing a wheeler

I make no comment

Andy
Reply With Quote
  #224  
Old 01-13-2011, 06:24 PM
Captain Avgas Captain Avgas is offline
 
Join Date: Oct 2005
Location: Melbourne, Australia
Posts: 1,868
Default

Quote:
Originally Posted by Fred.Stucklen View Post
I've provided a fair amount of transition training to guys getting ready to fly their own creations. All have been done it in RV-XA models. The one thing I stress is that the top of the cowl should be parallel with the runway on take-off AND landing.
The nose gear leg is KNOWN to be the weakest link in the landing gear. Respect it and it will serve you well. Abuse it, and it's not a matter of IF, but WHEN it will fail....
When I learnt to fly decades ago in a Cessna 172 my instructor spoke of the importance of keeping the weight off the nosegear on landing (as do probably all instructors) but in keeping with the generous safety factor on Cessna nosewheels he was not dictatorial on the matter. As long as it wasn't a flat landing and the nose gear touched down some appreciable time after the mains he was basically happy. On take-off it was just blast down the runway and pull back on the yoke when you wanted to leave the ground.

So I merrily flew over the ensuing years without mishap on take-off and landing convinced that I had quite good technique.

Flash forward many years and I'm building an RV7A and I decide to get some transition training from Mike Seager in Oregon.......BIG awakening!!!

Of the 8 hours I did with Mike at least 5 hours were just repetitive touch-and-goes. Learning to fly a nose gear RV with Mike is predominantly all about learning to keep as much weight as possible off the nose gear at all times....during taxi, during take-off and during landing. Mike's mantra is that you take the nose gear off the ground (right off the ground) on take-off as soon as you have enough elevator authority to do so (which is almost immediately in a typical RV) and let the plane eventually fly itself off the ground....there is NO rotation. On landing the nosegear remains off the ground until all elevator authority is FULLY exhausted. With time you learn to finesse the nose wheel onto the ground smoothly just as the last of your authority runs out.

What I learnt from flying with Mike is that my previous technique was grossly inadequate for a nose gear RV....and that I had no real concept of how bad my previous technique really was. I learnt that I had to re-learn my whole approach to take-offs and landings.

When I mention my learning experience under Mike Seager and the importance of keeping loads off the nosegear to other RV(A) pilots they invariably say: "That's exactly what I do". But strangely enough when I fly with these people I generally find that many of them have no real concept of keeping the nosegear off the ground to the full extent of elevator authority.

In other words many RV(A) pilots have terrible take-off and landing techniques...but they just don't know it. That is why video of good and bad RV landing techniques is so important to highlight the difference between the two. It's just something that cannot adequately be explained in words.
__________________
You’re only as good as your last landing
Bob Barrow
RV7A

Last edited by Captain Avgas : 01-14-2011 at 01:00 AM.
Reply With Quote
  #225  
Old 01-13-2011, 08:38 PM
rubber314chicken rubber314chicken is offline
 
Join Date: Mar 2010
Location: Cleveland, OH
Posts: 69
Default

Quote:
Originally Posted by MrNomad View Post
RocketBob, Doug, others:

While I am not an engineer, the gist of many of the comments I've read seem to agree that if the gear leg nut was higher off the ground, the incidence of rollover would decrease.

Others have suggested a larger front wheel & increased tire pressure (amongst other ideas) will get the nut further from the ground and reduce incidents. To a retired software guy like me, that seems logical.

Please take a look at the following two photos. Using Photoshop, I altered the angle of the fork. Said change will raise the nut further from the ground. I suspect it also alters the load on the gear leg and maybe even the cg a bit but I am not qualified to validate such claims.

Photo of the original fork....


Photo-shopped altered fork....
My thoughts as an engineering student is this is probably the best solution we can work out. I think that modifying the fork to fit a larger tire should also be done. The problems are though is if the fork is extended too much the gear leg will have to reinforced to handle the extra torque the same force on the wheel will apply to the leg. While this doesn't sound like a bad thing, the less that leg flexes (within design specs) the more of that shock is transferred to the airframe and the pilot. This could mean it starts cracking some other portion of the airframe from the forces on that gear leg.

As far as movement in the gear leg itself, the choices are basically to leave the leg as is, or redesign the motor mount to have a design like the -10. The current design appears as though it shouldn't be TOO difficult to redesign, but like anything, that is still a lot of work.
__________________
Alex
5.0 hours towards my ticket.
Just need to finish college and buy a kit...
Reply With Quote
  #226  
Old 01-13-2011, 08:58 PM
Sig600 Sig600 is offline
 
Join Date: Nov 2005
Location: KRTS
Posts: 1,798
Default

Quote:
Originally Posted by RV7AV8R View Post
When you compare these photos of planes with a similar nose gear but two without the problem there are other differences as well. Gruman and DA40 have wider lower stances. Just looking at these photos, which looks more unstable?
As someone who has substantial time in both the AA-5 and AG-5B I can tell you that the Tigers are VERY prone to prop strikes and nose gear collapse. It's a different structure as well. IIRC the tube runs back the length of the fuselage.

Had a buddy of mine get sued by the school he worked for when his student banged the prop on what was NOT a very hard landing. Shadey outfit, details outside the scope of this conversation.

Can't speak to the DA40.

I've got a lot of time flying a 6A off of very short grass, and never thought twice about the integrity of the nose gear. You have to fly the thing correctly, regardless of who built it, to it's limitations.
__________________
Next?, TBD
IAR-823, SOLD
RV-8, SOLD
RV-7, SOLD
Reply With Quote
  #227  
Old 01-13-2011, 09:29 PM
diamond diamond is offline
 
Join Date: Sep 2009
Location: Rochester, MN
Posts: 710
Default

Very nice video Doug
Do you recall what the crosswinds were at the time of shooting?
Reply With Quote
  #228  
Old 01-13-2011, 09:38 PM
PCHunt PCHunt is offline
 
Join Date: Feb 2007
Location: San Diego, CA
Posts: 1,670
Default DA-40

I've seen two DA-40's that had a prop strike. One on landing, and the other one was merely doing a 180 on the taxiway in front of my hangar, at slow speed, and in a SLIGHT dip, the prop hit.

Bad design, IMHO. Or else something was wrong with the nose gear. The nose tire was slightly low.
__________________
Pete Hunt, [San Diego] VAF #1069
RV-6, RV-6A, T-6G
ATP, CFII, A&P

2020 Donation+, Gladly Sent
Reply With Quote
  #229  
Old 01-14-2011, 12:16 AM
Snowflake's Avatar
Snowflake Snowflake is offline
 
Join Date: Oct 2009
Location: Victoria, BC, Canada
Posts: 3,932
Default

Quote:
Originally Posted by Sig600 View Post
As someone who has substantial time in both the AA-5 and AG-5B I can tell you that the Tigers are VERY prone to prop strikes and nose gear collapse. It's a different structure as well. IIRC the tube runs back the length of the fuselage.
Elsewhere in this thread (or maybe it's the "let's redesign the nosegear" thread), there are photos of the Grumman setup. The nosegear pivots around a horizontal tube that runs between the lower corners of the firewall. The tube is essentially the full width of the firewall. It's more like the RV-10 gear, IIRC.

I think the solution that people should be looking for is to make the same change you'd need to turn an original Van's non-swivel tailwheel into a Doug Bell tailwheel fork. Remove the almost horizontal sheet-metal swivelling portion, and replace it with a steeply angled, forged fork. That would raise the bottom of that pivot almost three inches, and remove most if not all opportunity for it to contact the ground. It would require serious redesign of the nosewheel pant, or perhaps switching to a simple spat trailing the wheel. Not the prettiest solution, I know. But it would probably take one heck of a beating before it failed.
__________________
Rob Prior
1996 RV-6 "Tweety" C-FRBP (formerly N196RV)
Reply With Quote
  #230  
Old 01-15-2011, 11:02 PM
vgb vgb is offline
 
Join Date: Aug 2007
Location: northern Cal
Posts: 111
Default Nose gear

It would be great if you always landed on a smooth paved runway but we have a runway in northern Calif that is paved and would be very apprehensive about landing there.
How about off field landings in a emergency.
When I'm flying and always keeping a eye out for landing spot I just figure I'll flip if I land in a alfalfa field' but what better place to put her down If I had to.
The gear should handle that.
I don't comment very often but the nose gear bugs me and sometimes wish I had built a taildragger.
Wait until the insurance companys figure out this nose gear problem and we will be paying more for a nose dragger instead of a tail dragger
Reply With Quote
Reply



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 02:19 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.