KR> Gap Seals
At 09:35 PM 4/5/2016, you wrote: >If you're ever tempted to fly around the patch without the gap seals >between stub wing and outer wing installed, be prepared for a >dramatically lowered climb rate. +++ You created two "little wings" instead of one big one, dramatically reducing the aspect ratio. With the gaps exposed you effectively created two wings with four tips. Larry Flesner
KR> Gap Seals
Jeff Scott wrote: > I tested both with and without the gap > seals. With several climbs to altitude and several speed runs. I > found no discernible difference in the performance numbers of my > aircraft between flying with and without the gap seals. I think the difference may be that you can follow the plans and end up with a big gap at the lower front edge of the aileron, or you can take some care and design the nose of the aileron so that it comes close to sealing itself. I'll throw out that perhaps Troy's RAF48 "per-plans" ailerons may have had a big gap at the bottom during straight-ahead flight, whereas both mine (N56ML) and yours likely seal better at the nose and therefore do a better job of sealing themselves, so gap seals don't help in our case. I can't vouch for Troy's experience, but can verify my own with the AS5048 wing and Frise aileronsno discernible difference with gap seals installed. Just FYI, N891JF came with gap seals installed, and I haven't noticed a lot of difficulty in making turns. But I also haven't experienced a stellar climb rate either. Maybe I need to do some testing, rip them off, and do some more testing. I'll have to find a fish scale that measures in grams though, instead of ounces of force. What I really need is a Corvair hanging off the nose of this thing! While we're on the subject of gap seals, I'll throw this out. If you're ever tempted to fly around the patch without the gap seals between stub wing and outer wing installed, be prepared for a dramatically lowered climb rate. And if you do it with only one missing and the other installed, be prepared for a serious roll tendency! How do I know this? Experimentation... Mark Langford ML at N56ML.com http://www.n56ml.com
KR> Adverse Yaw
I saw a notable difference in performance on my first KR installing gap seals, but it was built using three piano hinges only about 10 inches long spaced out evenly along the length of the aileron so there was a open gap from bottom to top. On my present KR I installed gap seals before I took it to the airport for the first flight, so I am not sure if there was any gain. It climbs, turns and flies great. Maybe I'll pull them off sometime and check the performance without them. Or maybe not. Roger Bulla -Original Message- From: svd via KRnet Sent: Tuesday, April 5, 2016 4:53 PM To: krnet at list.krnet.org Cc: svd Subject: KR> Adverse Yaw Hi All, I was just reading an old article by Stu Robinson in the March 1994 KR newsletter. In it, Stu points out that the aileron gap serves to increase drag on the down wing, thereby reducing or eliminating adverse yaw. However, I also read an article about how important gap seals are for increasing climb performance. So? Gaps seal? (I?m working on a RAF KR2s thats pretty close to plans.) Cheers, Owen ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options
KR> Adverse Yaw
Owen, Like several others it seems, I tested gap seals as well and quickly decided they provided no benefit and increased drag. I have scratch built RAF 48 wings on my KR2S. Rob Schmitt N1825Z Sent from my iPad > On Apr 5, 2016, at 5:53 PM, svd via KRnet wrote: > > > Hi All, > > I was just reading an old article by Stu Robinson in the March 1994 KR > newsletter. > > In it, Stu points out that the aileron gap serves to increase drag on the > down wing, thereby reducing or eliminating adverse yaw. > > However, I also read an article about how important gap seals are for > increasing climb performance. > > So? > Gaps seal? > > (I?m working on a RAF KR2s thats pretty close to plans.) > > Cheers, > Owen > > > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options
KR> weight and balance
Jon wrote- > It's quoted as 15 to 35 percent of the mac...which I believe is 41 inches > for the stock kr2...less for the kr2s. (Insert the sound of me slapping my hand to my forehead here)- why wasn't I paying attention? The KR2 wing is *not* constant chord for most of its span, so the MAC is certainly not 48" just because that's what the chord is at the center section! My bad. Re-stated then, and using 41" as the MAC, a CG range of 15 to 35% would be 6.15" to 14.35"... a range of 8.2". Now it makes sense when Neil Bingham writes in his "A Critical Analysis of the KR2" that in his opinion, the stated 8" range should be reduced to a 6" range, with 2" being taken off the aft end of the range. The numbers all make sense now; thank you Jon! Oscar Zuniga Medford, OR
KR> Message time stamp
Mark, check the time clock on your computer. I'm getting your messages before you send them. :-) Larry Flesner
KR> Adverse Yaw
> Stu points out that the aileron gap serves to > increase drag on the down wing, thereby > reducing or eliminating adverse yaw. However, > I also read an article about how important gap > seals are for increasing climb performance. So Gaps seal? +++ Gap seals are generally used to eliminate airflow from bottom to top or top to bottom of a control surface. The 6 foot piano hinge does that quite effectively on the KR aileron. Whether the considerable gap between the trail edge of the wing and lead edge of the aileron on the bottom of the wing has any ill effect is questionable. I did not seal that opening on the bottom of the wing and I get a very good climb rate. Others have professed that it helps the climb rate. All else being equal, I question that claim. As to adverse yaw, if built to plans ( aileron travel - 20 degrees up and 10 degrees down) on a wing eliminates adverse yaw in the KR. I can roll in to a 30 degree bank with my feet flat on the floor and the ball stays perfectly centered. The up aileron on the down wing creates more drag than the down aileron on the up wing or at least neutralizes it. The 3 degree washout on the wing called for in the plans also allows the ailerons to be fully effective through a straight ahead power off stall without any need for rudder input. I have tufted wing video to validate that. Any changes made to the above criteria will surely have some adverse affect and , as always, your results may differ. There is a wealth of info on the web. Just "google" aileron, differential aileron, frise aileron, etc. Larry Flesner
KR> Anyone know anything about this KR?
Anybody know anything about this KR? It looks like it has been around the patch - several owners in Valdosta GA for example. Thanks, Mark W N952MW (res) N50482 http://aviationdb.net/aviationdb/AircraftDetailPage N Number: 50482 Last Action Date2013-03-29 Airworthiness Date 1989-02-03 Expiration Date Manufacturer_Name CLARK Model Name RAND KR-2 Registrant Name R&R UNLIMITED INC Street 1232 CHOPTANK RD Registrant City MIDDLETOWN Registrant State DE Registrant Zip Code 19701 Country UNITED STATES Region Eastern Registrant Type Corporation Fract Owner Certificate Issue Date Status N-Number Assigned and Registered Serial Number 1 Aircraft Type Fixed wing single engine Mode S Code 51446127 Year Mfr 1984 Aircraft Category Land Builder Certification Not Type Certificated Number Engines 1 Number Seats 2 Aircraft Weight CLASS 1 Aircraft Cruising Speed 0 Airworthiness Classification Experimental Approved Operation Codes Amateur Built Engine Manufacturer VOLKSWAGEN Engine Model Name CONVERSION Engine Type Reciprocating Engine Horsepower/Thrust0 Fuel Consumed 0.00 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
KR> Adverse Yaw
And since this message was titled "adverse yaw", it's worth mentioning that most KRs, due to the differential aileron bellcranks shown in the plans, eliminate adverse yaw. Takeoffs, climbs, and landings are the only time that a slight amount of rudder is needed. The rest of the time the plane keeps the ball centered all by itself. As Larry Flesner says, "as long as I keep my feet off the pedals, the ball stays centered"... Mark Langford ML at N56ML.com http://www.n56ml.com
KR> Adverse Yaw
Owen wrote: > However, I also read an article about how important gap seals are for > increasing climb performance. See http://www.n56ml.com/troy/ for more on gap seals. Just looking at that big honkin' gap that you get when you build the wings per the plans, you can guess that there's an improvement in performance with gap seals. I built my wings with a Frise aileron, and with gap seals on that, I saw no benefit at all to the seals, mainly because the gap seals itself if you do it right. See http://www.n56ml.com/owings.html for more on that (near the bottom). Some folks would think that life is too short to spend this kind of effort on the ailerons, but I thought it was pretty simple and made a lot of sense. I will do my next one the same way, but will likely use a piano hinge at the top for simplicity and drag reductions (eliminating those external hinges from the airstream). Mark Langford ML at N56ML.com http://www.n56ml.com
KR> Adverse Yaw
"Gap seals?" Always choose better efficiency and performance. ?And put holes in your belly board. ;) Joe Nunley?CW2 US Army RetiredBaker JROTC Instructor?Baker Florida? Original message From: svd via KRnet List-Post: krnet@list.krnet.org Date: 04/05/2016 5:53 PM (GMT-06:00) To: krnet at list.krnet.org Cc: svd Subject: KR> Adverse Yaw Hi All, I was just reading an old article by Stu Robinson in the March 1994 KR newsletter.? In it, Stu points out that the aileron gap serves to increase drag on the down wing, thereby reducing or eliminating adverse yaw.? However, I also read an article about how important gap seals are for increasing climb performance. So? TeST TST-6 Duo (I?m working on a RAF KR2s thats pretty close to plans.) Cheers, Owen ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options
KR> Adverse Yaw
Hi All, I was just reading an old article by Stu Robinson in the March 1994 KR newsletter. In it, Stu points out that the aileron gap serves to increase drag on the down wing, thereby reducing or eliminating adverse yaw. However, I also read an article about how important gap seals are for increasing climb performance. So? Gaps seal? (I?m working on a RAF KR2s thats pretty close to plans.) Cheers, Owen
