Ideas for illiminating tip stall, or undersireable wing drop upon stall.
I am in the process of tweaking and fine tuning the setup on a BVM Maverick that I have converted to Turbine power. Along with the conversion I added about 6 to 7" of wing span on to each wing panel to help carry the added weight and to make it a one of a kind unique airplane. This is the second Maverick that I have converted and added wing span to and the first one flew like a dream in all respects with a fairly mild drop of the right wing when stalled. This stall occurred at a quite low airspeed and was not a factor during normal flights. The new airplane also flies on rails and quite well but likes to try to drop the left wing at speeds when I don't think it should be. This new airplane is on the heavy side (why Im not completely sure) but it is still within a reasonable flying weight for an airplane with this much wing and and having a thicker airfoil than other airplanes of this size and style. My goal with this airplane is to get it to stall straight ahead and at a reasonable airspeed. I made three flights last Sunday and did some stall tests at high altitude and regardless of flaps up, down part way or fully down it always falls off pretty hard to the left. Where this becomes an issue as you might guess is on landings. When breaking the sink and transitioning to a nose high attitude for landing if I get a little aggressive or rapid with with up elevator inputs that left wing will try to drop at a speed where it just shouldn't be and makes for some exciting and ugly landings. After last weekends flights I added three separate chunks of nose weight each weighing about 2.5 to 3 ounces for a total of about 8 ounces. I did not actually measure the effect of how far this moved the CG forward but having a fairly long nose it moved it a fair amount no doubt. I also programmed the ailerons for crow operation. I made the first flight with the full 8 ounces of lead and some up high stall tests and it still fell off on the left wing but at what seemed to be a more reasonable speed. Landing was much more solid but had some trouble getting the nose up very much for landing. I just remembered I also increased the flap deflection at full flaps a bit from the previous week. After the first flight I increased the upward crow defection a bit and took out 3 ounces of lead. Stall was still the same left wing drop at the same reasonable speed. Landing was still kind of flat and did not get the nose much above level for touchdown. All in all Im on the right track it seems. For tomorrows flight I am going to take out one more 2.5 ounce chunk of lead. The only other thing that I am contemplating doing is adding a small stall strip to the right wing only to see if I can get it to stall at the same time as the left wing and therefore fall more or less straight ahead. I have never done this or heard of it being done and Im wondering what the everybody thinks about this idea. Obviously a better idea would be to get the left wing to delay stall until the right wing stalls but I don't quite know how to do that ? And whatever I do I don't want to disrupt the way it flies otherwise in clean high speed flight. For an initial stall strip I cut a 4" length of brass tubing about 3/32 diameter and taped to the leading edge of the right wing about 5 or so inches outside of the wing root. The good news is im flying off of a vertically unlimited length of asphalt so if the stall tests at altitude don't go well I can always land fast and just let it roll. One thing that I have not done is check the airplane for lateral balance but my guess is its not to far out of balance. I will try to check it later tonight and so what I find. Im open to other ideas thoughts and suggestions.
Posted on: 5/18/2013 5:40 PM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11515506

RE: BVM brakes locked up ??
Well it turns out we were all wrong. I have a bad servo. It will only work in the direction of brakes ON, but will not return to the brakes off position except when rotated by hand. Then the next time brakes are applied they go on and stay on. Appolgies to BVM and to Ultra Precision Valves. The bad news is it takes quite a bit of disassembly and unbundling of servo cables. Had to remove the engine the bypass and one fuel tank as the wires run in an otherwise impossible to access area under the bypass and fuel tank. Having solved this problem I am on to my next issue. Watch for my post regarding tip stall and how to mitigate or lessen the severity of tip stall on this particular airplane.
Posted on: 5/18/2013 4:32 PM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11515450

RE: BVM brakes locked up ??
I have not flown this particular airplane with anything but the UP 6 valve. All in all I have had very good luck with these valves over the years. Till possibly now that is.
Posted on: 5/18/2013 2:33 PM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11515363

RE: RCU member and jet modeler in a serious accident
Thanks for the updates Les. Keep them coming as warranted. Here is to a full and speedy recovery.
Posted on: 5/18/2013 2:30 PM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11515362

RE: BVM brakes locked up ??
You may be right and the fact that both of them locked or more correctly stayed locked up after taxiing back to the pits and stopping at the end of flight number one does tend to make one think that for both to stay locked maybe it is a valve issue. On the other hand I have had this happen more than a few times over the last 20 years of flying BVM stuff and its happened with several different type of brake valves or actuators sometimes both brakes stay applied and most times it seems like only one stays applied. It will be interesting to see if I can get it to lock up in the workshop. I guess Im hoping I can so I can then figure out the source of the problem.
Posted on: 5/18/2013 2:25 PM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11515355

RE: BVM brakes locked up ??
I don't think it is the valve either. I think it is the brakes that are either sticking or somehow trapping pressure. I haven't had a chance to go look at them yet. I will in the next few hours however.
Posted on: 5/18/2013 1:21 PM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11515301

BVM brakes locked up ??
Ive seen this a few times over the years, usually as I recall it is one wheel or the other but not both. In my case to both wheels stay locked up (brakes on) even after bleeding off all the air pressure and with the brake valve in the off position. after 30 seconds or so with all pressure bled off the air tank the brakes finally released. I pumped it back up and they were again locked up without even applying any brake valve (UP 6). I once again let all the pressure out of the tank and after thirty seconds and a few applications of the brake valve on and off they released ? does anybody have a good idea whats happening and how to prevent it ? This all happened after the first flight this morning where they worked completely normally and they worked propery three flights last weekend.
Posted on: 5/18/2013 12:32 PM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11515265

RE: How to Correct Measured Thrust for Density Altitude?
I guess im still missing something. What are you going to with this info ? Use it to buy one turbine over others ? I mean Im sure its interesting and there is certainly no harm in it Im just not ultimatly sure what the point is ?
Posted on: 9/16/2012 2:30 PM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11230243

RE: Low profile retracts
More info would be helpful. How much does a JL Mirage weigh ? What is the diameter of the struts you plan to use ? Does it need to fit a certain bolt pattern ? What is the maximum thickness of retract that your airplane can accept ?
Posted on: 9/16/2012 5:59 AM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11229867

RE: How to Correct Measured Thrust for Density Altitude?
Seems to me the obvious question is why do care ? Its going to effect all manufacturers engines of similar size and thrust approximately the same amount and there is little if anything you can do about it except wait for a cooler day to go flying .
Posted on: 9/16/2012 5:53 AM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11229861

RE: WANTED Litco Alpha 4 Charger
Thanks. I got one a few weeks ago.
Posted on: 8/20/2012 5:30 AM by Author "turnnburn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=11199482

RE: Pilots for my 1/5 scale L-39
Thanks Joe c. Good looking pilot. A little pricey but not out of the question. It says they weigh 16 oz each which seems awfully heavy. With no pilots my airplane is alittle tail heavy and has lead in the nose ( I dont recall how much exactly, maybe 5 -8 ounces). I will certainly be able to remove most if not all nose weight. All if I put two pilots in.
Posted on: 8/1/2012 1:13 PM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11177472

WANTED Litco Alpha 4 charger
Looking to buy Litco Alpha 4 charger.
Posted on: 8/1/2012 8:21 AM by Author "turnnburn" in the forum "RC Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=11177180

WANTED Litco Alpha 4 Charger
Looking to buy Litco Alpha 4 charger
Posted on: 8/1/2012 8:19 AM by Author "turnnburn" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=11177176

Wanted Litco Alpha Charger
Wanted to buy Litco Alpha 4 charger
Posted on: 8/1/2012 8:18 AM by Author "turnnburn" in the forum "Giant Scale Aircraft - General"
http://www.rcuniverse.com/forum/fb.asp?m=11177174

RE: Pilots for my 1/5 scale L-39
I got one good suggestion but Im still looking and hoping for others. Preferably made in the US. Anybody else have some good suggestions ?
Posted on: 8/1/2012 7:19 AM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11177102

RE: Waco TX - Flying this Saturday the 28th
I had a feeling you guys would get your fill of 100 degree plus flying on sat.. I went to TMS this morn and made three flights trying out two new pair of sunglasses. The sky wasn't as gray and hazy as last week and I had a differnt gray airplane today. Saw it better but with my new glasses but Im still hoping for even better. PS. I dont balme you guys, the heat really takes its toll on us old guys ! !
Posted on: 7/29/2012 7:40 PM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11173455

RE: Waco TX - Flying this Saturday the 28th
Ahem David.............You are no spring chicken buddy. Based just on your lack of hair alone Id put you in the old category regardless of your actual age. Whats your new jet ?
Posted on: 7/29/2012 7:38 PM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11173957

RE: Pilots for my 1/5 scale L-39
Those look like they might work me, very nice. Thanks.
Posted on: 7/28/2012 11:07 AM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11172281

Pilots for my 1/5 scale L-39
Looking for some good looking, right sized pilots for my 1/5th scale L-39. I have room for about a 2/3 figure. In other words there is room for legs down to the mid thigh or maybe to the knee. Any ideas on differnt suppliers or manufacturers of the above.
Posted on: 7/28/2012 4:02 AM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11172022

RE: Replacement for JR 4131 Servo
Found a gentleman with 4 and have made a deal with him. Thanks guys.
Posted on: 7/27/2012 11:57 AM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11171429

RE: Waco TX - Flying this Saturday the 28th
Sunday is a better day for me. Might come sat.. might have to work. Might come sunday if some guys will for sure be there. Inother words i am my usual wishy washy maybe for one day or the other. I dont even know which day. What a loser ! ! LOL Have fun without me if I dont make it. Brian
Posted on: 7/26/2012 9:08 PM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11170805

RE: Replacement for JR 4131 Servo
I agree on primary flight surfaces, i use digitals whenever possible. I dont see the need or the advantage for using them on non primary flight surfaces like flaps, speed brakes etc etc.. in this case these are the flap servos on my 11 plus year old BVM 60" F-86.
Posted on: 7/26/2012 2:05 PM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11170331

RE: Replacement for JR 4131 Servo
also discontinued I think.
Posted on: 7/26/2012 10:08 AM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11170084

Replacement for JR 4131 Servo
I need to replace two 4131 flap servos. It is my understanding that these servos are no longer available. I prefer to use analog servos for this function if possible. I either need to find two new or used 4131's that someone can sell or find a suitable replacement that is the same physical size and mounting so they will drop right in. Does anybody know what JR analog servo that is still available that is a direct replacement for these ?
Posted on: 7/26/2012 9:55 AM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11170071

RE: Fire extinguishers.
Does the AMA require a certain minimum size Co2 extinguisher ? I would like to get the smallest one required I think. What is the correct or technical name for a "foam" extinguisher ? Sounds like a good thing to have in addition to the co2 and water one.
Posted on: 7/24/2012 10:30 AM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11167362

RE: Cant see my damn airplane !
Thanks Stonneeforcer, this is exactly the type of info I was looking for. Not only will this possibly help me but hoprefully some others as well.
Posted on: 7/23/2012 6:00 PM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11166543

RE: Cant see my damn airplane !
I have my eyes checked three times per year. Two required FAA flight physicals and I have an annual routine eye exam with an eye Dr.. I do not have cataracts. I dont have troubles driving or flying full scale at night with out distant vision correction. Interestingly I used to need distant correction but as my close up vision has slowly gone down hill over the last 10 or 12 years my distant vision has gotten better all on its own to the point where I am 20-20 in one eye and nearly 20-20 in the other eye and with both eyes I can pass 20-20 with a little struggle and strain. My eye Dr had told me years ago that some peoples distant vision improves as the close up vsion gets slowly worse. I guess Im one of the fortunate few that have this happen to them. When I had my last eye exam with the DR he was kind of skaking his head and telling what my distant vision was 5 or 6 years ago in my weak eye and how much it had improved. I dont normally wear any sun glasses when playing tennis but I did this morning I really did feel like I was seeing the ball sooner and better. I hope to get out to the flying field tomorrw afternoon I now have three pairs of differnet polarized sun glasses to try out. As the gentleman from Plano said it was just a really really bad hazy sky and my airplane is the worst possible size and color scheme for that kind of day. Especially with no sun glasses. The title of my post may be making some of you think the situation was even worse than it was. I obviously could see it ( with the exception of the one time where I totally lost it) I just couldnt see it the way I want to and need to for it to be enjoyable and fun. I have no intention of flying slower and closer in, that defeats the purpose for flying a turbine powered model for me anyway. I really dont think a differnt paint scheme would make a differance or much of one. I have been flying this airplane for a little over 11 years. The airframe is kind of beat up and banged up and isnt in my opnion a cnadidate for a new paint job. It will be time to retire it soon before some critical glue joint fails under the stress of flight. Give me some clouds for a back ground to help provide some depth perception and contrast and some appropriate sun glasses and I think I wll be fine. If I had this thread to do over again I would have just simply asked what brands and types of sun glasses guys are using and not made any mention of my two flights on Sunday. That was the purpose of my post to get reccomendations for which sun glasses guys are using and why do I could give the most popluar ones a try. I appreciate the other thoughts and suggestions but for now I will try to find the sun glasses solution that work best for me. I'm pretty sure I can find some that will get back to where I can fly the airplane comfortably and safely the way I enjoy flying it.
Posted on: 7/23/2012 5:57 PM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11166538

RE: Cant see my damn airplane !
Gee thanks Bob, like I need another reminder of my advancing years. I get one every time I look in the mirror ! And if that isnt enough I keep having passengers tell me how reassuring it is to see a pilot with gray hair, which I dont get since my hair AIN"T gray ! ! Its just not as blonde as it once was. The good news there arent any trees at the TMS parking lot, so I didnt have to worry about straining it thru a tree. I have a quite a bit bigger airplane, Tam F-18, also predominatly gray in color, have always had troubles seeing it too. I dug out a couple pair of sunglasses and will give them a try today and wil keep trying differnt ones till I can see MY DAMN AIRPLANE once again ! ! LOL.
Posted on: 7/23/2012 6:34 AM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11165574

RE: Fire extinguishers.
Wow, 26 lbs ? Makes me wonder if I have any agent left in extinguisher ? It doesnt have a gauge.
Posted on: 7/22/2012 7:49 PM by Author "turnnburn" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11165204