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katana snaps with minimal elevator input
Hello,
I have an ultra-rc katana (50 size) with a saito 82. The plane is balanced laterally. I have been experimenting with fore/aft balance all week. The trouble is, my plane keeps snapping with any appreciable elevator input. I can literally only apply like 15 degrees of elevator input before it snaps to the right. Needless to say, I have almost crashed numerous times pulling out of spins and stuff. The elevator halves are controlled by the standard cheapo wooden dowl/ Y wire setup and I am wondering if this is the problem. On the ground, it appears like the elevators move up and down equally, but maybe there is play in the system while in the air? The wing seems straight, so I don't think that is the issue. I plan on ripping the stock elevator setup out and installing two HS-81's in the tail. Do you think I am on the right track? I just hate to spend the $40 on the servos if it will end up doing the same exact thing. I searched here on RCU and it seems like nobody else has had similar problems with this plane. |
RE: katana snaps with minimal elevator input
Wood dowls will flex and it you only have one control horn for both elevator halfs, you are not getting equal movement on both sides, dual servos should fix that.
Does it do the same thing inverted? If you push? If it does, it sounds like balance. If it does not snap inverted, it should be the servo issue. |
RE: katana snaps with minimal elevator input
I didn't test to see if it snapped inverted or not. Unfortunately, I cannot test that anymore since I tore out the wooden dowl already in preparation for the dual servos in the rear. Thanks.
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RE: katana snaps with minimal elevator input
I have replaced the wood with a carbon fiber tube, it still snaps to right very easly. You are right about the elevator halfs. They dont move the same. at the max. distance they travel I always find 1-2 mm differance. I will not use 2 servos for this since the plane is already heavy. Mine wants to snap when it is slow or when I take off. So does it have anything to do with the angel of the engine.
Still I want to see your result with 2 servos. Good luck and regards. Zafer |
RE: katana snaps with minimal elevator input
Zafer,
I will let you know what happens with the two servos. Like you, I also thought maybe the engine angle and torque have something to do with it. Especially since I am using a saito 82 with a big, heavy 15x4 APC. I originally was concerned about adding the extra weight of the two servos, but I don't think it will end up being an issue. The standard servo I am using now weighs 1.5 ounces and the wooden dowl weighs maybe an ouce. I am replacing with two mini servos that only weigh 1/2 ounce each. I will shift the battery pack towards the nose to offset this weight in the rear, but overall I don't think the total weight will change. Steve |
RE: katana snaps with minimal elevator input
I am having the same exact issue with my Lanier Razor 3D. Even on low rates, it will snap out hard to the right. I've played around with the CG and it makes no difference. It balances laterally, but out of curiousity, I tried adding a half ounce of lead to the left wingtip with no change. I even tried adding elevator differential between the halves (which made it very interesting to fly) with no affect on the snapping out. I'm about ready to give up and strip the airframe. I bought this model used and it was in pretty bad shape. I had to replace the firewall among a few other things. I'm wondering if it could be related, atleast partially, to a wacky thrustline. I'm wondering what else I can try/check before I toss the airframe.. FWIW, I'm running a Saito .82 w/ APC 14x4W prop.
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RE: katana snaps with minimal elevator input
a snap is a type of stall
you do not have alot of pitch speed only about 45 mph what your airplain is doing is stalling and the prop tourq is rolling it over try a 12 8 just to see if the proublem goes away if so find a prop between the two where you can still do 3d and not be at the edge of a stall at all times |
RE: katana snaps with minimal elevator input
polikarpov i16, I have to disagree with you. My airplane is in no way stalling when it snaps. Even when pulling up from a high speed dive, the plane snaps to the right, indicating that slow speed stall is not the issue as you suggest.
Maybe its not a true snap- maybe its a roll to the right. Either way, the plane is in no way approaching a stall speed. I think what is happening, is that the right elevator is moving slightly differently than the left elevator. I am also sure that torque has something to do with it as well. |
RE: katana snaps with minimal elevator input
ORIGINAL: sbaugz polikarpov i16, I have to disagree with you. My airplane is in no way stalling when it snaps. Even when pulling up from a high speed dive, the plane snaps to the right, indicating that slow speed stall is not the issue as you suggest. Maybe its not a true snap- maybe its a roll to the right. Either way, the plane is in no way approaching a stall speed. I think what is happening, is that the right elevator is moving slightly differently than the left elevator. I am also sure that torque has something to do with it as well. It has nothing to do with the thrust of the motor. |
RE: katana snaps with minimal elevator input
It's true that a "snap" implies a stall. If you're sort of barrel rolling to the same direction every time you pull up (which looks like a fast, sloppy snap roll), uneven elevator deflection seems really likely, particularly where you have laterally balanced it. Is your linkage such that it applies force to the right half of the elevator more than the left half? That is, would the airflow tend to twist the left half toward neutral more than it would the right half when you pull up? I've seen a sport arf with this problem before.
I would guees that a warped wing could do this too. |
RE: katana snaps with minimal elevator input
I have the same combination with the saito .82 and a 14x4 prop also used a 13x6 a couple of times. and mine does the same thing, not quite a snap but more like a roll to the right. In 4 months of flying this plane I found that it does not roll out when inverted. Examined and measured elevator travel and have them exactly the same and still does it. Have travel set a little under 5/8" of travel. Contacted ultra and they told me to keep dialing in less travel till it goes away. Finally caught me out last saturday and because of not enough travel went in inverted. One thing I'd like to say though is that the plane does awesome knife edges and does great IMAC sequences. But if you cant trust it it will eventually bite you. Its a shame I really liked this plane but because of this behavior i wont be getting another one.
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RE: katana snaps with minimal elevator input
On the plane I saw with this problem, the two halves had the same throw *on the ground*, but you could tell by resisting the surface's movement with a finger that one would pull more strongly than the other
Now that I think about it, I had a jet which did something like this, and I think that was due to a droopy repair on one wingtip. |
RE: katana snaps with minimal elevator input
YNOT,
I guess you must be the expert then. My point is that my plane is not ending up doing a stall manuever. Maybe I used the wrong term- AlexF is probably summing it up correctly when he says its probably doing a barrel roll versus a stall. All things aside, I appreciate the assistance that some have provided here. I plan on installing dual servos in the tail, so I can be sure that the travel is exactly the same on each half. I will post my results here. |
RE: katana snaps with minimal elevator input
An Airplane should snap to the left with the power on and enough elevator. If you are dropping the right wing, I have little doubt that it is one of three things.
1. The right wing has a positive incidence compared to the left. (You will see this by the amount of right aileron trim you needed) 1. A bowed fuselage or built in right rudder causing way too much right yaw, or more likely 2 Too much right engine thrust. Get rid of your right engine thrust and you will almost certainly get rid of your right wing stalling before your left wing causing this snap. You would need a huge difference in elevator travel to cause that kind of snap. On full scale aerobat only one side of the elevator is trimmed and it doesn't cause the plane to snap any differently. |
RE: katana snaps with minimal elevator input
if your airplain is rolling to the right witch is diferent than a snap it has to do with the propeller
you do not notice it on a 40 size because you have a small prop the gyroscopic forces of a 15 inch prop are huge enough to roll your airplain over my 15 pound midwest cap 232 dose the same thing if i pull to hard it rolls to the right my friends full size super d exibits this behavior also when i pull hard on my cap i get about 1 quarter of a roll out of it you can test my thery witch i got out of an aerobatic mag just pull out of a dive with the engine off or at idle try a wood prop if you want to reduce it you cant get rid of it unless you go to contra rotating propellers or a jet engine |
RE: katana snaps with minimal elevator input
If I'm reading your first post correctly the elevator pushrod is a single wooden dowel with the metal rods in a Y to the individual elevator halves. Have a Modeltech Sukhoi that was set up the same (keyword - was). The dowel was not guided or restrained and under load it would always snap to one side increasing the throw on one elevator half and decreasing it on the other. Loads of fun. Trashed the pushrod, put two servo's in the tail, no more problems.
Mike |
RE: katana snaps with minimal elevator input
ORIGINAL: sbaugz Maybe I used the wrong term- AlexF is probably summing it up correctly when he says its probably doing a barrel roll versus a stall. This is exactly what my Razor is doing. I know for sure that the elevator halves are moving equally. I'll try removing any right thrust to see if it helps. Would up/down thrust have any affect on this? It looks like I have a little up thrust I need to get rid of as well. I'll try a smaller wood prop just to test that theory. |
RE: katana snaps with minimal elevator input
mikerjf, yes you are reading my first post correctly. I plan on doing exactly what you did. Hopefully it will work.
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RE: katana snaps with minimal elevator input
ORIGINAL: polikarpov i16 if your airplain is rolling to the right witch is diferent than a snap it has to do with the propeller you do not notice it on a 40 size because you have a small prop the gyroscopic forces of a 15 inch prop are huge enough to roll your airplain over The way to check this is to suddenly apply *down* elevator -- the plane should then yaw/roll to the left if gyroscopic procession is the cause. |
RE: katana snaps with minimal elevator input
Sbaugs, are you going to put smaller, like hitec 81 in the tail or full size servos? I would have to question the CG point, Its going to take a lot of nose weight to balance and the plane is already on the verge of being too heavy, it's going to take some creative work to balance it out. Maybe putting the battery pack in with the fuel tank will help. Obviosly by the post being written this seems to be a common trait with this airplane and everyone says the plane rolls to the right. I've tried 3 different props and took the right thrust out. If it was a pushrod problem why won't it roll out when doing outside loops. I can push as far down as I can doing tight outside multiple loops and it tracks straight, while with larger radius inside loops the plane will roll out to the right. I don't buy the differenial elevator theory. If it was it would dit it inside and outside.
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RE: katana snaps with minimal elevator input
that is exactly what hapens to my cap
it will not do a loop without a little rudder yank it hard and it is off to the right too bad it wont fit in my car with the child seat :( just hangs on the shop wall guess i will have to get something smaller again mabby after i buy the diapers :eek: |
RE: katana snaps with minimal elevator input
ORIGINAL: sbaugz YNOT, I guess you must be the expert then. To quote Kid Rock, "...some say I'm cocky...It ain't bragin....if you can back it up..." Something else to consider, do a pull pull set up on the two elevator halfs and leave your servo in the same location so you don't have to jack with the balance. This will ensure you have equal deflection. Pretty easy to do and not have to cut up a bunch of stuff. |
RE: katana snaps with minimal elevator input
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I am thinking about using an elevator bell crank (?) , what do you say ?
It will be a bit expensive but will have less weight. Regards. Zafer |
RE: katana snaps with minimal elevator input
Here is an e-mail I recevied from Brian at Ultra-RC. He asked that I share these tips with everyone to hopefully clear up some issues.
Steve, Thank you for your enquiry. Sorry to hear about this situation. I am hesitant in saying this, as many will view it as the manufacture saying what they have to in order to make a sale, but we are truly no experiencing the same issues as you are explaining. I do have many, many years of experience in RC. So I will do everything I can to help resolve this matter the best I can. I have read some of the posts on RCU......some members are saying the right things, and others are not, in my opinion. Here is a list of items I would check and comment on: First, our set-up on our plane is 100% stock. All the stock hardware and accessories with no modifications. We are using a Saito 82 which is demonstrated in our videos, and we are using all high torque ball bearing servos, only because this is what we had available to us. We are using Hitec 615MG servos on all control surfaces which provide a lot of torque. I would like to discuss the "rolling / snapping" tendencies which are mentioned. This clearly needs to be analyzed. Meaning, is it a slow rolling maneuver, or a high rate, more violent maneuver. If it is a slow rolling maneuver, it is not a stalling situation. If it is a more violent rolling maneuver, it is a stalling situation. There is such a thing as a high speed stall. Most don't fully understand what it is. Almost every airplane can be coaxed into a high speed stall. Too much throw is the first cause. Tail-heavy is another. A combination of the two can become very violent and uncontrollable. If it is a slow rolling maneuver, it can be a couple of issues. Flex in the control surface is one. More throw on one elevator vs. the other is another. Torque is another. Lateral balance, yet another. Inadequate servo torque is one more. There are some tests which can help to determine what is happening. You already know what the results are in a full speed pass or a dive. Try a half throttle pass and see if the symptoms still exist. Also, fly inverted and fly both full and half throttle and test the results to see if they are the same. The reason for this, if it is the elevator pushrod, in one direction it pushes, in the other it pulls. The pushing side is usually always the side that flexes, and also puts more strain on the servo. If it does not do it inverted, I would suggest it is the pushrod, or inadequate servo torque causing the problem. Another thing, if it is performing a more violent type maneuver, than it is more than likely a high speed stall which would require reduced elevator throw, and possible changing the CG. My test for this is full speed loops and reducing the elevator until they can successfully be completed continuously without any rolling / snapping tendencies. This is the rate of elevator I would use for normal flying. You may need more elevator for landing, although not usually, and if this is the case, you will need to run dual rates. We use full elevator, as much as we can get, for 3D type maneuvers. However, we perform these maneuvers at low throttle settings and rely on power to be the elevator....controlling altitude. But you have to keep in mind, this plane is a Katana, not a Funtana, and is sensitive in high alpha maneuvers which require skill. Funtana's provide you with a sense of security as it is a sport scale airplane designed for fun with thick airfoils for added stability. OK.....enough rambling.......here are some points of interest. 1. Elevator Pushrod - There has been a lot of discussion here about this issue. This type of set-up has been used for years successfully.....however, this type of set-up can present problems. First, un-equal elevator deflection. Second, lack of support, sometimes causing flexing. Third, you need adequate servo torque to support the system. This type of system is very difficult to make perfect, but can be done. This type of linkage almost always provides for more strength (holding power) in one direction vs. the other. This is due to the fact the servo is pulling in one direction and pushing in the other. Most inconsistencies and flex occur on the push side. The pull side is usually very strong. This is why the plane may perform better in one axis vs. another. 2. CG - The center of gravity on this size plane is very critical. Meaning, 1/4 ounce of weight will make a noticeable difference in the CG location and the flying characteristics. CG is an adjustment of personal preference. This is why there is a range. Also, it is based on your level of flying. With the problems being noted, I would recommend changing the CG to a more nose heavy position along with the other changes in the elevator control throw as mentioned in an effort to solve the situation. Once the situation is resolved, additional changes can then be made to "fine-tune" the model for your type of flying and feel. 3. Lateral Balance - Lateral balance will have an affect on the way a plane flies. I once saw a plane drop a wing on take-off and landings all the time, but fly well in the air. Once it was balanced properly, it flew perfectly. This check should always be part of the set-up process and pre-flight checks before flying a plane, but in my opinion, bases on what you are saying, I do not think this is the issue in your case. 4. Right Thrust / Engine Torque - This could very easily be the issue too. Part of my first flights and initial set-up, I always check the engine thrust. Here is how I do it......Vertical climbs, hands off. I pull up straight and level and punch the throttle. I then take my hands off the sticks and watch the plane. If it veers off to the left, it needs more right thrust. To the right, it needs left right thrust. If it pulls to the canopy, more down thrust, and if it pushes towards the gear, more up thrust. I keep making changes until it performs a perfect vertical upline hands off. This technique always works for me. Now, there is such a thing as too much power / torque. I once had a plane that was so over powered, on vertical climbs, the plane would do a slow roll to the right. Flying straight and level, it would roll to the right. On take-off, if I punched it hard, it would torque over to the right. So, here is another test. Fly straight and level at half throttle, plane trimmed perfectly, and punch the throttle, then throttle back, if the plane starts to roll to the right, you have a torque issue and it may be difficult to solve. One way to remedy is to experiment with props. In my case, I was so over-powered, I experimented with 3-blade props which helped significantly, but still didn't solve the problem. I ended up making am ix in my computer radio with the throttle to my ailerons to re-trim the plane with different throttle settings. For me, it worked fine and the plane was enjoyable to fly from that point. By the way, I am referring to a giant scale plane with a large gas engine. 5. Wing Incidence - Lastly, this could very easily be the issue too. One wing positive and one wing negative will easily cause the same issues you are mentioning. If you have not checked the incidence with an incidence meter, I would highly recommend it. Even the planes that are pre-set from the factory should be checked. It is VERY easy to change the incidence, and most don't even know when they did. So in closing, (sorry for the long winded email), I do believe a dual elevator installation will help. BUT, you will need to refer to all the above recommendations to fully solve the problem and set-up the airplane. There are many successful Katana's flying out there so I know it can be done. I am also aware of the posts, so thus the lengthy email to you. Please share my comments with everyone..... my hope is to help everyone so they can thoroughly enjoy the Katana. Please do not hesitate to contact me with any additional comments or questions. I look forward to speaking with you again soon and I really hope your changes and attention to these details will prevail in a success for you. Sincerely, Ultra-RC Brian Hughes |
RE: katana snaps with minimal elevator input
A stall has nothing to do with airspeed, it is angle of attack. If you meet or exceed your critical angle of attack (angle of attack at which the wing stalls) the wing will stall regardless of your airspeed.
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RE: katana snaps with minimal elevator input
Impressive letter from Ultra RC. BIG thumbs up to them.
The 2 in 1 bellcrank work well, however a pain in the butt to get in. It would easier to do the pull pull set up. |
RE: katana snaps with minimal elevator input
Impressive letter...Yes, True....mostly
(Torque) "Now, there is such a thing as too much power / torque. I once had a plane that was so over powered, on vertical climbs, the plane would do a slow roll to the right. Flying straight and level, it would roll to the right." Only if your propeller was turning backwards. Have you ever seen an airplane torque roll to the right? I think he meant left. (CG) "With the problems being noted, I would recommend changing the CG to a more nose heavy position along with the other changes in the elevator control throw as mentioned in an effort to solve the situation." Actually a more rearward CG, closer the CL will result in a slightly higher AOA before a stall occurs because you are offloading some of the weight from the wing. That is also why a plane with a more rearward CG will also fly faster. I do applaud Brian from Ultra-RC for writing this letter. It shows a great deal of knowledge, concern and support for his products. |
RE: katana snaps with minimal elevator input
Hi I have the same plain and mine fly's like a dream. Make sure youd SG is not to far back and the elevator should not move more than 20 mm up or down on maximum input on the stick. I do Sportsman Precision Aerobaticks with mine and I must tell you there is already about 3 people that also whant to buy the same plain. Maibe you can try to move your SG more to the front, mine is about a 90 mm back of the leading ege of the wing closest to the fuse.
Try that and see what happens. Good luck Arrie |
RE: katana snaps with minimal elevator input
Well,
I installed the twin HS81 servos in the tail. Now I have precise elevator movement of both halves. The plane still snaps very easily, in fact, it seems worse. The plane is dead on with lateral balance. As for the CG: I added 4 ounces of lead to the nose and the plane balances at 4 inches back, which is in middle range of the recommended CG point. I also have the battery pack and receiver way up by the fuel tank. Short of adding more lead, I can't get the CG much further towards the nose, although as mentioned its in the middle of the range anyways. This balance point was with an empty fuel tank. I also checked the thrust line by going straight vertical. The plane tracks straight up without veering off to the right or left, indicating that I probably am good as far as my thrust line goes. Maybe I need to accept the fact that this plane won't tolerate extreme elevator throws. I guess I am used to my Extreme Flight Yak with 50 degrees of elevator throw. I can give full throw at any speed and the Yak won't snap in the least bit. Anyways, at this point, i may consider selling the katana as its becoming frustrating trying to figure this out. |
RE: katana snaps with minimal elevator input
I think most folks around here use the term snap and don't fully understand what the term means. A snap is a condition where one wing(or a portion of a wing panel) stalls before the other that causes an abrupt roll in the direction of the stalled wing. A snap-roll is a maneuver that uses this one-side-stalled condition to rapidly rotate the airplane around it's axis on purpose. If your plane does this and you didn't mean for it to then you have what the full size pilots call a departure from controlled flight.
With every airplane I set up one of the first tests I do is to apply full elevator at full throttle and see if the plane will track 3/4 of the way through a loop without departing. I usually find that I will get a departure while either entering the loop or at the top and sometimes it will get me at the exit but the throttle is usually reduced on the back side of the loop so if you depart there your really using too much throw. This ALWAYS has been the result of too much elevator throw. I land the plane, dail out some throw and repeat the test again and keep doing this till the plane will track through a loop at full power with zero departures. This becomes my low rate setting and I fly the plane there till I either lose it or sell it, whichever comes first. The intersting thing is that most of the modern designs have such huge surfaces that they reqauire VERY little throw to get the job done effectively. I usually find that most planes have more than adequate elevator authority with as little as 10 -12 degrees. You also need to understand that ANY change in balance will affect this setting and you'll need to re-fly the plane and do the full-pull test again to make sure your plane will not stall and depart. As for high rate set up that is a completely different animal and is another topic entirely. |
RE: katana snaps with minimal elevator input
I understand your rational behind dialing the elevator throw down to a point where it is still effective while maintaining control----- but I have dialed mined down so much that loops are absolutely huge at full input. Anything more and it will roll or snap out. I would say I can only use maybe less than 10% throw before it snaps, or whatever you want me to call it.
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RE: katana snaps with minimal elevator input
IME snappy planes have either too much elevator throw, the number one culprit IMO. If your loops are huge then you definately have something else going on and my next culprit would be the elevators are traveling unevenly. The ONLY way to veryify that they are in syc is to get a pair of clothes pins and CA some pushrod wire or coat hanger wire on them, about a foot long peice is usually sufficient. Clip the pins on the elevators and bring the tips of the wires close to each other and bend them till they are right next to each other. Now turn on the plane and move the elevators through their full range, the wire tips should track each other perfectly, if they don't your gonna have issues with the plane.
Next is the CG, I have found that NOSE heavy will result in a much more violent departure than a tail heavy condition will. My favorite method for checking balance is to roll inverted and let go of the sticks at about 3/4 throttle. If the nose drops and the plane heads for the ground at a steep angle your way nose heavy. If the plane climbs your way tail heavy. If the plane flies perfectly level(rare) your neutral. I prefer then to drop the nose just slightly, one or 2 clicks of down trim would get the flying a level track at the most. After that if nothing seems to be helping you either have a model that has an incidence problem or one that is grossly over weight. Incidence is easy to check with a meter, if you really want to get it bang on(and this can make a HUGE difference in ALL of your models BTW) buy 2 meters and put one on the tail and one on the wing at the same time, compare readings between the two. Do the same on the wing panels and then on the same panel but one on the tip and the other on the root of the wing to check for warps. Something I have done for quite a while is to set up my planes by first adjusting the radio sub trim to get the servo arms at 90 degrees to the servo case then adjust my linkages to obtain zero degrees of incidence on elevators and ailerons. You should also check up/down thrust at this time as well. After setting up the plane I fly it and usually there will only be a couple of clicks of trim required, if any at all. Most of us tend to (eyeball) where the surfaces should rest while in the neutral position, especially the ailerons, which can result in a built-in couple of degrees of unintended posative or negative incidence. A couple of degrees doesn't sound like much but it can be the difference between a model that flies extremely well and one that has nothing but problems. Just out of curiosity what is the span on your plane and what is the weight of the model with the tank dry? |
RE: katana snaps with minimal elevator input
span is 53 inches. I have no idea what the weight is. According to Ultra R/C, they fly the same set-up with saito 82 and they don't have any problems. It doesn't "feel" like its overweight while flying either.
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RE: katana snaps with minimal elevator input
Try increasing your expo on your ailerons and do the loop thing. You may be getting into the ailerons on the elevator imput. Its easier to do than one may think...Watch your rudder when you throttle up, you'll see what Im refering to...
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RE: katana snaps with minimal elevator input
53 inches is a pretty short span, it's a .46 sized plane with that span. Ideal weight for a plane that size should be no more than 5.5 lbs. and no more IMO. Remember on models of this size the ounces add up fast since they are so small to begin with. If it's at all possible to take any weight off the plane it can only help out.
I have no idea what your set up includes but if I were setting one of these up I would avoid metal geared servos, battery packs larger than 600 mah and the fuel ank should be no bigger than 10 ounces. The .82 is a pretty big engine for a plane that size and consequently brings problems of it's own to the party. Also the .82 is a torque monster and will really work a plane with that short of a span. I would be willing to be the engine mount right thrust was factored for a .46 two stroke which has much less torque and consequently isn't correct for the .82 thus requiring some fine tuning to get it right. |
RE: katana snaps with minimal elevator input
All the components are fairly lightweight. Battery pack is a stock hitec 600mAh 4.8V. Servos are 2 HS81s on the elevators, HS545 on the ailerons, HS605 on rudder, and futaba s3004 on throttle. Saito 82 is pretty light itself, comparable to some .46 2 strokes out there. Anyways, your point about the saito 82 being too much engine may be right, although as mentioned previously ultra r/c used the 82 in one of their planes.
Anyways, without beating this thread to death, I am probably going to try and sell the plane anyways. Thanks for all the advice. |
RE: katana snaps with minimal elevator input
sbaugz,
Just try it before you sell it........ Get rid of the right thrust! As you found out, moving the CG forward does not help a stall and can make it worse. An airplane should look like its falling off to the left on a full power up-line.... You can always mix in right rudder with throttle if you really need to have the straight looking upline. This is how ALL full scale and many Pattern & IMAC fliers are getting the stright up-lines. If you have so much right engine thrust built in that the airplane looks straight up in a full power upline it will be yawing to the right all the rest of the time. This is the one sure way to make the right wing drop (stall) before the left. If you still don't think it's engine thrust try this. Take off then add a bunch of left rudder trim & then trim the ailerons for level flight. Now yank back hard on the elevator on high rates. The left wing should now stall first. A good 3d pilot can make either wing stall first or make both wings stall at the same time with Yaw (rudder) control. |
RE: katana snaps with minimal elevator input
Ok my input. Watch your wieght!!!!!!!. I HAD a saito 91(14x4), 2300 NIMH battery and all stock servo's and the thing snaped BAD 2 times. I crashed and ordered parts. After last crash I went back to a magnum 52 (12.25x3.75)and put a 9g servo, under the cowling for the throttel and stock battery . Also took off the wheel pants. Put one servo in tail for rudder and 3001 on elivator in normal spot. Battery is behind the tank. Also conected the elivator's -- with carbon rod I had. It still has the dual control going back to. (that I do not like.) It made its first landing last week like this. Flew a lot better. It does knife edge good no great- superb. I did one hard loop and it did seem to roll a little bit but far from a snap. I have installed a Hitec 225BB on the elivator. To save some more wieght. But I do not like the way it centers the elivator. The hitec's that I have had new and used have all centered like crude. If there is a mod to make them center better email me. I will fly it like this. Hope it makes it back in one piece. Just watch that weight. I did not like the saito 91 to heavy and to much power. This wing area is small. Also did not use the yellow man holder thing. The virtical is great with this setup. If you want a 3d plane buy something else to over power. This thing does fly good. That saito 82 is light. I would put a smaller prop on it to check it out. and a small servo on throttel. hope this helps. [email protected]
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