Re: KR> KRnet Digest, Vol 6, Issue 14
Aileron mass balance arm. Have an idea for a mass balance arm and would like peoples thoughts or opinions on it or if it has already been done this way before without any issues. what about an arm made up of fiberglass to a lay up say 3/16 or 1/4" thick and say 2" wide and moulded to shape so one end can extend inside the cord of the aileron and flox in and with a tab extending off it and 4" wide as a bolting face to the inside of the spar then can be shaped to extend over the spars into the mass balance pocket without cutting into the aileron wing spar then the raised portion that extends over the spars can then be faired back onto the aileron skin, anyone consider this strong enough or ridiculous idea? thought behind it is as moulded there is no stress point in any bends as could be in alloy or steel, or just stick to steel and be done with it? ___ Search the KRnet Archives at https://www.mail-archive.com/krnet@list.krnet.org/. 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> KRnet Digest, Vol 6, Issue 12
Robert Gill The plane was built to plans, standard kr2 with AS5046 wing to standard length, tail modified to a longer stab by 6" elevator reduced by 4", all controls were rebalanced after painting. plane was frequently flown to 180Kt on the old engine with now problems at all with no signs of any issues, the plane was almost a direct copy of Troy Pettiways to look at and built to the same way with incident angles and the plane was beautiful to fly, have now been going over the airframe mostly wings with a fine tooth comb to inspect everything to find maybe a cause of the failure, have found no evidence of a bird strike, as there were bird there at the time, but a witness has told me the saw something small fall off the plane just before it happened traveling at the same speed, can only assume it was the mass balance as one is missing (from the still attached aileron). So far only solution I can come up with was the shudder that comes from the engine around 3100 rpm which is what I was trying to solve, severe enough to shake the whole airframe which I think fatigued the mass balance mounting causing it to come of sending the aileron into flutter, under 3000rpm engine ran smoothly. up till then had done 8 test flights trying to tune the engine to the recommended rpm by changing pitch (Bolly 3 blade 56") on the prop to recommended level flight at 3200rpm each time testing at 3200rpm was for approx. 5 seconds then was going to re-jet the carb to get the right EGT's as all indicators were showing it was running slobbering rich, EGT's high 500 dec C should be between 680-720. the 3200 rpm was finally achieved on that flight on previous level run, did take a shallow dive to get it to wind up to there and then it could hold it constant it was the second run when it happened. ___ Search the KRnet Archives at https://www.mail-archive.com/krnet@list.krnet.org/. 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> 912 ULS
HI, i'm after some info about installing a Rotax 912 ULS 100 hp in my kr2. I am replacing the Revmaster R2300, I am sick of spending more hours fixing the engine than flying it. about 150 hrs flight time and 300 hours repair time.what I need to know is, has any one out there have a 912 ULS in there KR2, what my concern is with the reduction drive at 2.43 equating to 2380 RPM at the prop would a 58" diameter prop be enough for take off, then in min cruise power with 2057 RPM at the prop is it still going to work, currently with the R2300 'when its going' I am getting 135 KT cruise at 3000 RPM.what I am guessing is with a 58" prop (max dia I can safely go) it would have to have a hell of a lot of pitch on it to get the engine loaded right, then with that much pitch am i going to have more trouble with the prop stalling say when trying to take off? prop manufacturer here in Oz. said that that engine and there prop would give me an estimated cruise about 150-160 kt cruise WOW!! if it works. I know its not the correct way to look at this but 2000 RPM at the moment i'm barely keeping the plane flying?If anyone has installed a 912 with a 58" prop what prop are they using, and how much success are they having with it.Another engine option I am considering is the new D-MOTOR LF26 specs look really good to suit a KR2, direct drive, 92 Hp @ 3000 RPM, water cooled, EFI, 88 Hp @ 2800 RPM for cruise,8 liter/hour 2.1 gal/hour for the yanks, (that near the doubles my fuel endurance), 67 kg ready to fly weight and its tiny and apparently very quite. and has down loadable diagnostics which can be sent to the manufacturer for analysis or tuning, and cheaper than a 912 'not by much'.
KR> Revmaster R2300
Hi all, I Thought I would put my two cents in about the Revmaster R2300 as I have one of these in my kr2, When I'm not working on it trying to figure out the bugs, when its running right it is a great engine, after about 18 months of playing with it I am now getting 140 kts cruise and 1200 fpm climb at gross , so that i think is pretty respectable, and can now not stress to much on it performing properly. But the problems I have had with the engine at times I've been ready to burn the plane! thinking I would never get this thing right. A few times in the early hours of it flying it I had to do emergency 180 turn backs on climb out as the engine was not going to make the full circuit, with CHT's going through the roof at 300 deg C+. (screen only only goes to 300 got there in about 10 sec from take off, and EGT's 950 deg C+. (last flight when the heads finally cooked). a list of the faults I had with it are. 1/ ign. timing set at approx 40 deg btdc, which cooked the heads within 10 hrs from new (timing was factory set!) with a timing light shown it was correct at the prop flange, but found it a with dial ind. on piston #1 while stripping the engine down. 2/ aluminium push rods 6 out of the eight failed in 40 hrs, now replaced all with steel ones (rod ends crushed into the alloy tubes) and yes they were rubbing on the push rod outer tubes . 3/. oil leaked out like a sieve every were since new, can never seem to get one to take up from out the back of the engine, 4/. constantly lapping valves particularly the exhaust valves, 20 hours ago had the heads professionally ground and re seated and just recently 3 exh. valves started leaking again and had to re lap (about 2 hours ago). and feels like i am adjusting tappets every 5 hours. temp figures:- CHT's on average in climb approx 180-190 degs C., 140-150 deg C in cruise 90-100 on descent.EGT's around 680-720 deg C, in climb and about 600 deg C. in cruise.Oil Temp about 60-70 deg C, pending on day temp.So the engine does run pretty cool and I am running only on 98 unleaded fuel, no ethanol. (cant afford AV gas over here or justify it.The engine now has 130 hours on it (with 500 hundred hours spent working on it!)And as I said earlier when its going properly it does perform very well, but the quality of manufacture does let it down! Or mine must have just been a Friday build.
KR> Revflow carby
To "Roger Bulla" everything that you described is exactly what is happening with mine, I can get it to run smooth at full WOT. on climb and really high EGT's, (and no its not on the lean side) then reducing the throttle into the mid range and low end, the mixture control is so far back its almost to the point of no fuel, an example yesterday for touch and goes I was doing is why I don't like it, was when I went to open the throttle approx 1/4" i forgot to richen the mix first before moving the throttle and I swear that if i hadn't have got onto the mix when i did the engine would have stopped and I would have been though the fence on the end of the strip, you need a throttle that will respond straight away at least with a small amount of throttle movement.Let me know how you get on with your Revflow Rodger, like you, i like the design of the revfow and alternate flow ram air intake, If i have to change carbs i also will have to reshape my cowl to suit.
KR> flying, KR 19-8322
In reply to Brian Kraut, my KR has the std Diehl landing gear and plans built tail wheel assembly on it with an asphalt high speed roller blade wheel (its a bit small but works ok). Granted when 3 point landing you are semi along for the ride when you settle on, as there is no visibility over the nose, I did make my own 3 piece canopy for it which is more vertical on the side than a bubble so i get slightly more forward view by looking down the side of the cowl than most would. I also think the wing tip design plays a big part in it as well as i made my as modified hoerner tip, did a lot of home work on the subject when deciding on what to do with them. (great vid on youtube about them and how to make them), so far to count i have done 12 landing, only 2 are wheeler rest are 3 pointers, I am no high time pilot, have not been current in fixed wing for nearly 10 years and pretty much flew this thing straight out of the box after i got current again in a 'bottom end' high performance plane as required over here to get current for mine, (jabiru 120), and tail endorsement in a single seat version on a kitfox. (Grandmother could fly that thing) for me to say the KR is a hard plane to fly NO WAY!! definitely got that KR grin every time i go up!While I am, here how the hell do anyone tune a revflow carby I can tune the mix at the needle to run smooth at full throttle soon as i pull it back under about 80% and to idle, the engine sounds so rich it wants to drown! and have to continuously fumble between throttle and mix while flying.Some suggestions would be handy.
KR> flying, KR 19-8322
I'd like to make a little comment about flying my KR2, Granted I have only clocked up 5 hrs on it now in the last 3 day since I started flying it myself, but all the hype i had read about while building it, with being a very sensitive if not over sensitive plane to fly is absolute rubbish! or I just got it right! I cant stay out of this thing!!! it has to be possibly the easiest plane I have ever flown! the mod to to stabilizer by stretching it's span 6" and cutting the span of the elevator down by 4" has really paid off! still light, powerful and responsive but by comparison to the fin and rudder which is pretty much stock to the plan very light and very easy to catch you out and to get in trouble with over control on the ground with the tail up, but comparison between elevator and rudder responses, elevator would be half as sensitive as the rudder but still just as powerful, if the rudder is anything to go by, If any one is like myself as a low time pilot and building one, I could not recommend anything better than the mods that Troy Petteway did to the tail, just wish I did it to the fin and rudder. Test pilot stated to me just before I flew for the first time that, he has never flown a plane that is so easy to 3 point land! and he is right! I could only imagine how sensitive the elevator would be if done to the plans. Would be very nervy on the first couple of landings until you got used to it.
KR> kr props
Thanks for the replies about props, test pilot flew the plane again this morning and the local plane legend was there again as well and everyone agreed that the prop needed to be trimmed down and after what a few of the kr netters had suggested also, I bit the bullet and trimmed 1/2" off each tip. now my static rpm has increased by approx 80 rpm, from 2370 to 2450, not quite as much as I had hoped. test pilot will take it for another run tomorrow to check to see how much more i will gain in flight. (i hope i don't lose to much on performance!)If all goes well, hopefully I will get to take it up myself tomorrow as well for the fist time, I did do a couple of runs down the strip this morning flying it approx 10' of the runway, love the aileron response just need to get used to the elevator, must have been funny to watch when i was trying to settle back on with ballooning, over controlling with elevator.
KR> kr props
Hi all, does any one have any advise on props, my kr2 has now had its second test flight on it, The prop is a Tonini gt, its a 56*44 and i am only getting 2800 rpm on climb and 2900 at 140 Kts. (160 mph) Revmaster claims full power is 85 hp. @ 3200 rpm. the climb also appears to be lacking. engine is a revmaster R2300. I am missing 3-400 rpm. would trimming down the diameter a little at a time give me back my missing revs.My other thought is, the engine now only has 1.2 hrs on it from new, can the engine develop more power as it runs in, so am i jumping the gun thinking about the prop yet.Test pilot claims the 'little KR' (smurf jet) is a beautiful little plane to fly, well balanced in all controls and, the mod to the tail (same as Troy Petteway's ) has really paid off. not overly sensitive throughout the whole speed envelope and still powerful enough for full control at low speed. (big relief !!).Other thing is i may have ballsed up on my tail incidence as the nose keeps wanting to lower even with full up trim, I added a second adjustable trim to the control bell crank at the elevator with bungee cord to between the seats and that still required a lot of pull to trim the plane out. ortest pilot is also a light weight (he is), I haven't checked the weight and balance figure but I am guessing he has put the CG fwd of the fwd limit. (as a 85 kg (187 lb to you yanks) pilot and full head tank I am 1/4" aft of the fwd limit). I have been told this was to be expected on the first flight (nose down trim that is)One more thing, I have lagging on my header pipes can this cause me to have higher than expected EGT temps approx 50c and higher. (122f for the yanks), lagging was put on to protect wiring and coils, on the R2300 with individual ignition coils, the front exhausts run parallel under the head and approx 1/2" away from the coils.
KR> first flight
KR 19-8322 here in Aus. finally flew her first flight today, (and I am still buzzing) only for one circuit tho as there was a high EGT alarm but bar graphs were in the green, so it was landed on caution , Test pilot said it flew well just slightly nose heavy, just a few minor things to fix up now then on with the rest of the test fight hours.here a video of the first flight.http://www.youtube.com/watch?v=ZA1rSoiwS2I
KR> first flight advise
Thanks guy's for the reply, I had not even considered the thought of flying several different aircraft before mine but it is a good logical idea and i know were it is coming from as I have driven a lot of different machines over the years, from small underground loco's to giant mine face shovels and you need to approach each one differently and feel what the machine is telling you before you act. but for this purpose I am only limited to a small few planes. And by the way if any one is on the hunt for tail wheel came across this, a Tail Wheel Assembly and hardware. from fisher flying products, looks like a neat unit. --always great to find something after you have already made it!!--And thanks Mark for the offer for my link but my my web site is already there in the builders list. unless you had something else in mind, in any case it's OK, its out there for anyone to look at.
KR> first flight advise
Thanks for the first flight test plan Mark, I will be seriously studying that.here is a couple of specs on mine if it helps any one for my first flight advice and what to expect,I pretty much built mine exactly the same as Troy Petteway's. Based on photos and his tail specs.It is a standard KR2 , apart from the tail. and fixed gear (Dhiel) T.G.I increased the stab span by 6" on both sides and reduced the elevator by 4" on both sides, pretty much same as Troy's (built that way with fear in mind of pitch sensitivity in the early stages), Increase the height of the fin by 4"Wing is the AS5046.Empty weight is 635lb./288kg Mean CG, aft face of fwd spar is 54.5" from spinner back plate. CG. with full fuel (head tank and wing tanks) and 1 pilot is 971lb./440kg. CG. is 1/4" fwd of mean CG. Head tank only with 1 pilot is 894lb/405kg, CG is 1 3/4" fwd of mean CG. Engine is a 85hp Revmaster R2300 with Revflow carb and prop is a Tonini Bro. GT 57" * 44". Pilot weight based on 187lb/85kg. "i'm a little lighter than that!"if any ones interested in some pics there is some here of it http://www.lilausydreamkr2.com/general-pics.html.
KR> first flight advise
Just wondering if any one can give me a comparison of flying a KR to flying a jabiru or a soneri. at the moment i am doing some time in a jabiru to get the skills going again after a few years of not flying a 3 axis 'been busy building' and the jab has a training wheel up front mine doesn't, i have also been offered some time in a soneri, these are the only planes in the area were i live that i think may come close to the handling of a KR, because hopefully when i get home from sea this time i will be taking mine to the airport for its first flight so whether i do the first flight or i can get someone else to do it, i can have or give some little advise on what to expect.
krnet@list.krnet.org
Hi all,I finally just completed my KR2 on the 1/NOV/2013, 2 years 3 months and 1800hrs (yipee!), and after final weigh in 4 days ago i have an mt. weight of 635lb/288kg and a gross weight of 1162lb/527kg that's with 26.5gal/100L. fuel (Aus. is a big place!) and based on two 85 kg pilots on board.I am now about to go back to sea for four weeks so I now have to sit wait to get the permit to fly in the mail, and to get the first flight out of the way and thinking of that, I had a pilot organised to do the first flight for me, he came around yesterday to do his own inspection on it and could not wait to do the first flight UNTILL he tried to fit in it! He couldn't even get his knees under the dash let alone close the canopy. He didn't look that much bigger than me! considering that I had built it around myself. Bit to be said for the size of the KR!So what tips can I get for the first flight? If I end up doing it myself.
KR> KR and pilot
My condolences to Ben's family, I only found out a few days ago, I was hoping to catch up with him during my leave home from sea this time, so I could get some time in his before I fly mine for the fist time.
KR> aileron pushrods
from my previous question regarding aileron pushrods I am searching for solid steel rivets for the aileron push rods and can't find any, I would prefer to use the steel rivets, as the rod ends and tube are chrome steel, were I think with alloy or monel rivets there will be corrosion issues over time. (indifferent metals = corrosion. as I was taught at school.) any one have any other suggestions.or another option. would steel cherry rivets be considered strong enough to do the job? in place of solid.
KR> Aileron pushrods
This is more addressed to Mark Jones (N886MJ) I am nearly ready to make the aileron push rods for my kr2.I have ordered and received the parts that you listed from an old archive message.AN490HT8P rod ends 1/2" * .035" 4130 tube and the MW-4 bearings. next question is. What rivets did you use to attach the rod ends to the 4130 tube? So many rivets to choose from!
KR> aileron horns
Any one else at the point of having to make the aileron horns as i think this is going to be a real problem getting material to make them, aircraft spruce does not supply 2 1/2" *4" *1/8 6061 any more. does any on have any left over for making them that they would like to get rid of?
KR> serial numbers
I have a question regarding serial numbers as I am about to start a request for the the rego numbers here in Australia and they require the serial number. I have been told that the serial number should be printed inside the front cover of the construction manual but the only number there is an EAA# 51###. (5 numbers long don't seem long enough for a serial) but is this the serial number?The manual is pretty old, last revised 1977 rand robinson. I hope this is it as I am getting close to completing the plane now and I dont really want to buy a new set of plans just for the number.
KR> oshkosh
Hi Guys.This is not really a kr question. But my partner and I have decided to fly over to states and see Oshkosh next year and this will be my first time out of Australia (If they let me!!).But does anyone have any good suggestions for accommodation around Oshkosh and what would I be expecting price wise. Next question is How do we get to Oshkosh as we will be flying into L.A. but from there I still haven't figured out what to do. Is there an airline that flys to Wisconson direct from L.A and how does the airline system work over there can a person just show up and book a ticket there and then on the day or better to book in advance?I suppose more importantly does any one have any suggestions for what the chief cook can do as she not a aviation junky like me and she thinks she will get a bit bored after a day or two of looking at planes.And will any other kr builders be there to catch up with (there's a KR question).Robert Gillwww.lilausydreamkr2.com
KR> aileron control horns
Hi all, I have been looking for some 4"*2" 1/8 ally for making the aileron control horns but cant find any. Does any one out there know of a supply of it, or of a substitute that could be used?
KR> brakes
Hi all,Found some thing that could be use full to any one that is interested, if there at the stage of installing brakes particularly the master cylinders these are the same ones that my father has installed in his PL-4A they bolt directly in the middle on the back of the rudder pedal pate with a push rod to the toe brake, very simple when you see it.http://www.airheart-brakes.com/la-master.html
KR> 2300 propeller
Hi all, I have a question, I tried looking up in the archives to try and work out what would be a recommended size for a prop to suite the revmaster R2300 but could not find anything, I did find though it seems to be a common 52" size diameter for VW engines and I think I remember reading some were about .7 being a multiplier for horse power to give you a pitch range. but I could not find any one that has said what they are using, is there any one out there that is running a Revmaster 2300 and what size prop are are you using are you happy with it or would you recommend more or less pitch.
KR> fuse skins
Robert GillHi, I have a question about the best way to surface and level the ply fuse skins aft of the cockpit area without adding to much weight, the skins have bowed inward up to 3/8" in some ares particularly just under the top stringer, should I glass the skin first with deck cloth then use foam to build the areas out then lay another layer of deck cloth over the areas that have been leveled out, or put the foam straight on the ply skin then glass over that, or glass the ply skin as before and just keep filling with micro until the surfaces are flat and smooth ( how thick can you go with micro? ), or does any one else have a better idea.
KR> holy spar
Robert Gill. Tassy Australia.Hi all I have a small problem with a hole in the shear webbing on the front of the fwd spar, the hole was originally patched by someone else but that was ok because they were going to use the retract gear were I am not, I am going to be using the diehl fixed gear as a tail dragger. I carefully scaped away the patch to level the spar for the mounting brackets (I did expect there to be a hole why else for a patch), but can i get away with this size hole and leave it in the webbing? or should i scarf in a new piece of ply. Why or how this hole got there i have no idea! but seems to be cut into it.-- this is the link to an image of the hole for some one to give me an ideahttp://www.lilausydreamkr2.com/uploads/1/0/3/7/10378354/7420344_orig.jpg
KR> tail spars
I have a question about using the tail rib templates on the existing preshaped spars for the KR2.with the stab foamed up between the spars and the tip template glued in place would it be safe to fill the gap to make up the thickness of the spar by pouring in polyurethane foam then sand down to shape, or would it be better to cap and shape the spars with some more spruce, I ask this as my spars have already been sized to the original plans with the 5/8" sq. tips and i want to use M. Langfords profiles.
KR> as5046 profile
Hi from Robert Gill in Tasmania Australia,I have just started construction on a standard kr2 project that was given to me, the boat hull is complete and the center spars have been glued in place the stab and elevators have been built but not glassed or glued to the Fuse.I have been reading Mark Langford's artical on the design of the AS5046 profile and he refers to others that have modified there kr2s with the new profile.My question is while mine is at this stage of construction can the AS5046 profile be used on the standard KR2 and use the construction methods as explained in his artical, by raising the TE spar to decrease in incidence and increasing the main spar thickness with extra capping and then the tail incidence to match, will this work? and will it work with the standard tail profile. His artical seem to only refer to the KR2s.
