Re: KR> KR2 damaged elevator
Mark Thanks for the advice. I have studied your webpages for some time now and it is clear you have good experience! Regards Deon On 13/01/2017 02:18, Mark Langford via KRnet wrote: Virg wrote: > Pitch sensitivity is an overblown item, Virg Now that I have put over 1100 hours on a KR2S, and almost 300 on a KR2, I feel qualified to say that there is a pretty large difference in pitch stability between the two. Yes, the KR2 is entirely controllable, but then mine is flown at the very forward end of the CG envelope. Having said that, I did PIOs (pitch induced oscillations) for many of my first KR2 flights. Jim Hill, who put several hundred hours on his KR2 before he broke it in half and extended it to become a KR2S, once said "let go of the stick?...You can't let go of the stick...YOU'LL DIE if you let go of the stick! By contrast, my KR2S is simply not an issue to fly. Keeping the CG forward cannot be overstressed, either way. From my experience, any speed penalty is practically impossible to quantify. To answer the question of how to lengthen the horizontal stabilizer, Troy Petteway did it (and reported a big improvement in stability) by adding 6" onto the tips of the stab by simply adding foam, sanding to shape, and wrapping with two or three layers of carbon fiber. That plane is still flying, last I heard. He also decreased the size of the elevator to lessen the over-control tendency. See http://www.n56ml.com/troy/ for photos, both near the top and near the bottom (actual construction of both horizontal stab mods and "new airfoil" wings. One thought on rebuilding the elevator is to simply cut it in half and remove it, and built another one from the template set at the bottom of http://www.krnet.org/as504x/ . Build the new h/s spar with a "ship lapped" joint in the middle, with a widened bellcrank plate as a metal splice joint. The aft deck is non-structural, so turning some of that into a removable fairing will provide access to the bellcrank for dealing with the hardware. There are other ways to deal with it, but this is one way I'd consider... Mark Langford m...@n56ml.com http://www.n56ml.com ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
Re: KR> Pitch sensitivity
What Chris describes is not at all unusual. A number of aircraft fly better in an aft CG as the elevator gets too heavy with a forward CG. A C-182 is a good example. A 200 horse Muskateer is another. It flies better and is easier to land if your CG is a bit aft simply because the elevator gets so heavy during landing when the CG is forward even though both configurations are still within the acceptable CG range. Flying with a forward CG in these planes requires so much aft trim that the down force on the tail and trim drag is enough that the plane flies slower in a forward CG. The stock KR has so little stabilizer that an aft CG configuration can get very pitchy. I flew my KR with the small tail for 500 hours before cutting it off and building a larger tail. I've flown it another 650 hours since with the larger tail, so I think I can comment on this from a position of first hand experience. After building a larger horizontal stabilizer and elevator, I really don't notice much difference in handling between a forward and aft CG in my KR as long as I stay within the 6" CG range as recommended by most builders. I built the new stab and elevator to an 8' span using the templates Mark provides on his web site. -Jeff Scott Los Alamos, NM --- > Could you go into further detail about "how" it flew better with a forward > CG than an aft CG? Sure, the plane under normal conditions (no baggage) would require significant up trim to unload the stick, and when pulling power, would drop the nose unless you held onto the stick. "Lawn dart"is a description used more than once. Conversely, with plenty of stuff in the baggage compartment (at or near aft CG limit), the plane seemed to "float" in balance and handled much better and was faster to boot. A pure dream to fly. This was discussed often. It was considered by some to be good practice to ignore the front half of the CG envelope. It is possible that the CG envelope was shifted a bit forward than it should have been and in fact I spoke with someone in good authority that the aft limit was quite conservative and flying AT the published aft limit would in fact produce good results, and it did. > See http://www.n56ml.com/wb/index.html for more on the KR aft CG, which I'm > pretty sure is common to most aircraft. This story should scare you...it > certainly scared me! I actually had read that last year, another well written piece and in fact I am sure I saved it to PDF as well in my KR own knowlege base. ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
Re: KR> Pitch sensitivity
> Could you go into further detail about "how" it flew better with a forward > CG than an aft CG? Sure, the plane under normal conditions (no baggage) would require significant up trim to unload the stick, and when pulling power, would drop the nose unless you held onto the stick. "Lawn dart"is a description used more than once. Conversely, with plenty of stuff in the baggage compartment (at or near aft CG limit), the plane seemed to "float" in balance and handled much better and was faster to boot. A pure dream to fly. This was discussed often. It was considered by some to be good practice to ignore the front half of the CG envelope. It is possible that the CG envelope was shifted a bit forward than it should have been and in fact I spoke with someone in good authority that the aft limit was quite conservative and flying AT the published aft limit would in fact produce good results, and it did. > See http://www.n56ml.com/wb/index.html for more on the KR aft CG, which I'm > pretty sure is common to most aircraft. This story should scare you...it > certainly scared me! I actually had read that last year, another well written piece and in fact I am sure I saved it to PDF as well in my KR own knowlege base. ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
Re: KR> Pitch sensitivity
Kayak Chris wrote: > with all this talk about pitch sensitivity, one common mention is > using forward CG. What is up with that? My last plane really liked aft > CG (within the envelope obviously) and flew MUCH better there. What > happens to a KR at aft CG? You had an odd bird if it flew better with an aft CG than a forward CG. Could you go into further detail about "how" it flew better with a forward CG than an aft CG? See http://www.n56ml.com/wb/index.html for more on the KR aft CG, which I'm pretty sure is common to most aircraft. This story should scare you...it certainly scared me! Also see http://www.askacfi.com/5222/forward-cg-vs-aft-cg-which-is-better-and-why.htm as a starting point. With the CG at the absolute front of the limit, my KR2 does require a trim tab on the elevator or it'll dive pretty quickly. I didn't set it up that way, but that's the way it is. Almost everything I installed after I bought it was to move it aft, but it wasn't enough to move it very far. My KR2S is usually flown right in the middle of the range, maybe slightly aft, but even with heavy passengers there was not a huge difference. Go really aft though, and you are living very dangerously, as discussed at http://www.n56ml.com/wb/index.html ... Mark Langford m...@n56ml.com http://www.n56ml.com ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
Re: KR> Pitch sensitivity
with all this talk about pitch sensitivity, one common mention is using forward CG. What is up with that? My last plane really liked aft CG (within the envelope obviously) and flew MUCH better there. What happens to a KR at aft CG? ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
KR> Pitch sensitivity
At 03:45 PM 1/12/2017, you wrote: Pitch sensitivity is an overblown item, Virg ++ Pitch sensitivity is NOT overblown but it also SHOULD NOT be an issue for the knowing pilot. It is easily accommodated on the first flight and actually makes for a nice flying sports car type aircraft. I once saw a chart that listed the KR2 (original plans built I assume) as close to the F86 in stability based on physical dimension and wing and tail surface area. The closest thing I can relate my KR to (24 inch longer fuselage, standard KR2 tail dimensions) is driving my Buick or Toyota down the interstate at 70 miles per hour. I can change lanes with very little movement of the wheel (much larger than my control stick) with the KR having much lighter control surface push back. If you can drive an automobile at moderate speeds then you can fly a KR and enjoy it, given acceptable C.G. location of course. There is a reason the 2S was lengthened and given more tail area. Mark Langford might be the best authority given his many hours in both the 2s and then the 2. Jeff Scott reported on the difference after enlarging the tail surfaces in his KR and I'm guessing Mike Sylvester can enlighten us on switching from a Cessna 150 to the KR2s on his recent first flight. Keep the C.G. in the correct location, anticipate the sensitivity, and enjoy flying your KR... Larry Flesner ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
Re: KR> KR2 damaged elevator
Virg wrote: > Pitch sensitivity is an overblown item, Virg Now that I have put over 1100 hours on a KR2S, and almost 300 on a KR2, I feel qualified to say that there is a pretty large difference in pitch stability between the two. Yes, the KR2 is entirely controllable, but then mine is flown at the very forward end of the CG envelope. Having said that, I did PIOs (pitch induced oscillations) for many of my first KR2 flights. Jim Hill, who put several hundred hours on his KR2 before he broke it in half and extended it to become a KR2S, once said "let go of the stick?...You can't let go of the stick...YOU'LL DIE if you let go of the stick! By contrast, my KR2S is simply not an issue to fly. Keeping the CG forward cannot be overstressed, either way. From my experience, any speed penalty is practically impossible to quantify. To answer the question of how to lengthen the horizontal stabilizer, Troy Petteway did it (and reported a big improvement in stability) by adding 6" onto the tips of the stab by simply adding foam, sanding to shape, and wrapping with two or three layers of carbon fiber. That plane is still flying, last I heard. He also decreased the size of the elevator to lessen the over-control tendency. See http://www.n56ml.com/troy/ for photos, both near the top and near the bottom (actual construction of both horizontal stab mods and "new airfoil" wings. One thought on rebuilding the elevator is to simply cut it in half and remove it, and built another one from the template set at the bottom of http://www.krnet.org/as504x/ . Build the new h/s spar with a "ship lapped" joint in the middle, with a widened bellcrank plate as a metal splice joint. The aft deck is non-structural, so turning some of that into a removable fairing will provide access to the bellcrank for dealing with the hardware. There are other ways to deal with it, but this is one way I'd consider... Mark Langford m...@n56ml.com http://www.n56ml.com ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
Re: KR> KR2 damaged elevator
Pitch sensitivity is an overblown item, Virg On 1/12/2017 10:42 AM, Deon-tsrc via KRnet wrote: Hi Virgil The KR2 apparently suffers from too much pitch sensitivity. Later designs resulted in the KR2S which has a longer fuselage length increasing the moment arm of the tail. Another idea was too increase the surface area of the horizontal stabilizer (see Mark Langford's discussion about this). Since my A/C body is already built, option 2 is my only option. I know one can get used to the sensitivity but in the early stages we that are used to C172's struggle (so I am told). Having the CoG in the front also helps. I hope I answered your question? Deon On 12/01/2017 15:55, Virgil N. Salisbury via KRnet wrote: What pitch sensitivity ? Virg ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
KR> pitot tube location?
Rick, Here is the web page about building his pitot tube. Should give you everything you need. http://www.n56ml.com/fairings.html -- Wayne DeLisle Sr. KR> KRnet Digest, Vol 5, Issue 3 Rick Cochenet wiharley69 at yahoo.com Sat Jan 7 11:52:24 EST 2017 Previous message (by thread): KR> FOR SALE Next message (by thread): KR> pitot tube location? Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] On my KR2 project i am missing the pitot tube and am not sure where they mount them on the KR? No sign of any previous openings in the wings, possibly on the belly? and what type are builders using and who sells them? Thanks... Rick. ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
Re: KR> KR2 damaged elevator
Hi Virgil The KR2 apparently suffers from too much pitch sensitivity. Later designs resulted in the KR2S which has a longer fuselage length increasing the moment arm of the tail. Another idea was too increase the surface area of the horizontal stabilizer (see Mark Langford's discussion about this). Since my A/C body is already built, option 2 is my only option. I know one can get used to the sensitivity but in the early stages we that are used to C172's struggle (so I am told). Having the CoG in the front also helps. I hope I answered your question? Deon On 12/01/2017 15:55, Virgil N. Salisbury via KRnet wrote: What pitch sensitivity ? Virg On 1/12/2017 1:47 AM, Deon-tsrc via KRnet wrote: Good day I was thinking that in the process I should reduce pitch sensitivity by enlarging the tail area as well. So removing the aft spar of the horizontal stabilizer and install a longer one. Suggestions? Regards Deon ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
Re: KR> KR2 damaged elevator
What pitch sensitivity ? Virg On 1/12/2017 1:47 AM, Deon-tsrc via KRnet wrote: Good day I was thinking that in the process I should reduce pitch sensitivity by enlarging the tail area as well. So removing the aft spar of the horizontal stabilizer and install a longer one. Suggestions? Regards Deon ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
