HELP - CAN'T land my first gasser.. 30cc PILOT RC SBACH 342
03-13-2017, 12:59 PM
#1
Thread Starter
HELP - CAN'T land my first gasser.. 30cc PILOT RC SBACH 342
I have flown lots of RC planes over the years including larger ones like the Top Flite cessna 310 but this is my first gasser. I am a licensed pilot also. I Just got a SBACH 342 30cc from Pilot RC and it flys great but I can't land it. The plane comes in Very HOT!!! is this normal for a large 3D plane? If i approach with power it takes me 300 feet to slow it down and 3-point. If i approach at idle i typicall stall after the roundout. is this normal for a plane with such a low wing loading to have such poor gliding characteristics? Is it just prop drag? I know a harrier style landing it an option but I would prefer not to land that way unless i have to. I am running an 18x6 on DLE 35.
Any advice is appreciated. Thank you.
Any advice is appreciated. Thank you.
03-13-2017, 02:20 PM
#2
My Feedback: (2)
My bet: If you look at your elevator that's been trimmed for straight and level flight, it's going to have some "up" trimmed into it. That's nearly a guarantee the plane is nose heavy - regardless of what the directions tell you regarding CG.
Forward CG also pretty much guarantees high landing speeds.
If you're CG is ahead of the wing tube, that would be the 3rd indicator.
It really sounds like you need to trim for proper CG. On a plane like that, I would keep moving the CG back until you find yourself flying with a neutral elevator. That will be really close....
Forward CG also pretty much guarantees high landing speeds.
If you're CG is ahead of the wing tube, that would be the 3rd indicator.
It really sounds like you need to trim for proper CG. On a plane like that, I would keep moving the CG back until you find yourself flying with a neutral elevator. That will be really close....
03-13-2017, 02:24 PM
#3
Use this website to get a CG point. Putting it at 25-30% of the MAC is a good place to start. Dan.
http://edgewoodflyers.com/GroupResou...4/Default.aspx
http://edgewoodflyers.com/GroupResou...4/Default.aspx
03-14-2017, 05:27 AM
#4
Thread Starter
I hate to admit it but you might be right. Spec is for balance on the rear of the wing tube but i have the cg forward of the front of the tube. I also notice it doesn't want to lift off easy. It screams down the runway and i have to apply significant up elevator to get it to lift off. I will re-balance. I hope this helps because i love the plane but it lands like a warbird... LOL. Thanks for the help!
03-21-2017, 07:26 AM
#6
I also agree with the possibility that the CG of your Sbach 342 30cc is off set, however I would like to add something to this thread.
Since Somenzini and his early followers got the 3D mania started in our hobby, a nearly infinite number of designs has been launched in the market. Now if you went through this history, you would find that the first prototype of these planes (Extra's, Edge's, Yak's, Sukhoi's, etc...) has always been of large size; at least 100cc and above. Then for commercial reasons the manufactures began to offer ARF's of smaller sizes to accomodate the budget of many of us.
The unfortunate result is that small 3D-aerobatic scale-look-alike planes don't fly well. They are often too responsive, they do not float, they have got bad attitudes and so on.
I am saying this because in my club I have seen many times the same plane, from the same manufacturer but in a smaller size flying in a total different way than its bigger counterpart.
It is all about physics: Surface area goes by square versus weight that goes by cubic. Going small, they will never meet each other.
4sylvester, besides CG adjustments, I would recommend you to install a lighter engine. 250 to 400 gr less would make your landings much easier.
Since Somenzini and his early followers got the 3D mania started in our hobby, a nearly infinite number of designs has been launched in the market. Now if you went through this history, you would find that the first prototype of these planes (Extra's, Edge's, Yak's, Sukhoi's, etc...) has always been of large size; at least 100cc and above. Then for commercial reasons the manufactures began to offer ARF's of smaller sizes to accomodate the budget of many of us.
The unfortunate result is that small 3D-aerobatic scale-look-alike planes don't fly well. They are often too responsive, they do not float, they have got bad attitudes and so on.
I am saying this because in my club I have seen many times the same plane, from the same manufacturer but in a smaller size flying in a total different way than its bigger counterpart.
It is all about physics: Surface area goes by square versus weight that goes by cubic. Going small, they will never meet each other.
4sylvester, besides CG adjustments, I would recommend you to install a lighter engine. 250 to 400 gr less would make your landings much easier.
03-21-2017, 08:07 AM
#7
Have to agree with all that's been said before regarding your model having a very forward CG, and also it sounds like you are running a too small a prop on your DLE35 as a 20 x 6 or 20 x 8 is more in keeping with props for that size engine.
03-21-2017, 08:31 AM
#8
4Sylvester Pilot R/C Sbach with a w/span of 73", w/area of 1,000 + sq. ins and a weight of 10.5 lbs cannot be considered an overweight or overpowered model by any stretch and is well suited to a 35cc size engine. Just my .02 cents.
03-21-2017, 11:05 AM
#9
Well let's talk licensed pilot stuff..... 
An airplane, including a model, will fly slower than it will glide right? So, you need to get into the habit of setting it up in a slow fly condition on the final approach. Another full scale deal; do not mess around with the elevator much if at all. Remember, elevator controls attitude and power/throttle controls altitude so use your throttle to control the descent rate. It's much easier to do this by "blipping" the throttle as finding the perfect setting isn't going to happen during that short time on final.
Take it up a couple of mistakes high and practice setting up and doing slow flight.
As the other guys have mentioned and you seem to have figured out it might be an issue; get your CG set correctly to get the beastie into the air and then adjust it so the model fly's the way you like it.
An airplane, including a model, will fly slower than it will glide right? So, you need to get into the habit of setting it up in a slow fly condition on the final approach. Another full scale deal; do not mess around with the elevator much if at all. Remember, elevator controls attitude and power/throttle controls altitude so use your throttle to control the descent rate. It's much easier to do this by "blipping" the throttle as finding the perfect setting isn't going to happen during that short time on final.
Take it up a couple of mistakes high and practice setting up and doing slow flight.
As the other guys have mentioned and you seem to have figured out it might be an issue; get your CG set correctly to get the beastie into the air and then adjust it so the model fly's the way you like it.
03-22-2017, 04:50 AM
#10
My Feedback: (23)
I fly the 36% Pilot version with a DA 100.
In order to land this puppy I have to get the the idle as low as I can and land it with that throttle setting or it just keeps flying. I agree with the above, as you might need to adjust your CG.
Also, you might try using a lower pitch prop.
paul
In order to land this puppy I have to get the the idle as low as I can and land it with that throttle setting or it just keeps flying. I agree with the above, as you might need to adjust your CG.
Also, you might try using a lower pitch prop.
paul
03-22-2017, 08:26 AM
#11
Thread Starter
Correction, my prop is 19x8. I am moving the CG back and moving my batteries forward so i will be saving some significant weight. Still not convinced this is a going to be a great "landing" airplane because of scaling issues pointed out but hopeful. I will repost when she is in the air again. Thanks for all the help.
03-24-2017, 02:19 PM
#13
I would like to know the answer to this as well.
This may have been true 20+ years ago but I don't believe this to be true today. Bigger almost always flies better but to say small scale aerobatic planes don't fly well is a bit much. In my opinion.
This may have been true 20+ years ago but I don't believe this to be true today. Bigger almost always flies better but to say small scale aerobatic planes don't fly well is a bit much. In my opinion.
03-24-2017, 11:19 PM
#14
We forgot to say that the way a model airplane flies is a very subjective thing. We have a couple of buddies down here who could fly a rock as well as a trainer with the same ease. Although you have flown many planes, while airborne, you may want to pass the TX to a friend you trust and get your Sbach 342 a second opinion. I have seen this quite often in our club and it actually helps in finding out solutions.
The other thing is that reliable manufacturers, like Pilot-RC, provide true CG positions in their plane manuals. Therefore if you said where is now located the CG exactly and the weight of your plane, I am quite sure that some of our friends here would be able to guide you more precisely to a better flying attitude.
The other thing is that reliable manufacturers, like Pilot-RC, provide true CG positions in their plane manuals. Therefore if you said where is now located the CG exactly and the weight of your plane, I am quite sure that some of our friends here would be able to guide you more precisely to a better flying attitude.
03-25-2017, 04:20 AM
#15
My Feedback: (2)
We forgot to say that the way a model airplane flies is a very subjective thing. We have a couple of buddies down here who could fly a rock as well as a trainer with the same ease. Although you have flown many planes, while airborne, you may want to pass the TX to a friend you trust and get your Sbach 342 a second opinion. I have seen this quite often in our club and it actually helps in finding out solutions.
The other thing is that reliable manufacturers, like Pilot-RC, provide true CG positions in their plane manuals. Therefore if you said where is now located the CG exactly and the weight of your plane, I am quite sure that some of our friends here would be able to guide you more precisely to a better flying attitude.
The other thing is that reliable manufacturers, like Pilot-RC, provide true CG positions in their plane manuals. Therefore if you said where is now located the CG exactly and the weight of your plane, I am quite sure that some of our friends here would be able to guide you more precisely to a better flying attitude.
The thing is, named maneuvers, when flown by a "small" plane or a "big" plane, are the same. They are flown the same, and judged the same, big and small alike.There's no extra credit given for flying a maneuver well with a small plane, nor is there one expected.
Regarding "true" CG position given by a manf., it's pretty much fact many flying the same plane will have a range of positions they favor. So how is the "true" CG position you speak of arrived at? Or, could you instead be thinking of a position that might be a good place to start - to be tuned to an individual's personal taste, favored position arrived at only after a lot of flying/testing? If you can agree to that, would you also think that this position the plane manf. supplies might be towards the front of the "range" generally flown?
I agree many thing are subjective, and I'd also agree the larger RC stuff has the potential for much higher power to weight ratios, allowing them some advantage. The rest of your comments I struggle with.
Last edited by ahicks; 03-25-2017 at 04:22 AM.
03-25-2017, 05:38 AM
#16
Well sir, maybe you haven't witnessed some of the same flying action I've seen. If you stand by the thought that compares the way small planes fly to the way a rock flies, maybe you haven't seen an electric indoor plane flown well - by an 8 year old? This pretty much blows the "small planes don't fly well" theory right out of the water in my estimation.
The thing is, named maneuvers, when flown by a "small" plane or a "big" plane, are the same. They are flown the same, and judged the same, big and small alike.There's no extra credit given for flying a maneuver well with a small plane, nor is there one expected.
Regarding "true" CG position given by a manf., it's pretty much fact many flying the same plane will have a range of positions they favor. So how is the "true" CG position you speak of arrived at? Or, could you instead be thinking of a position that might be a good place to start - to be tuned to an individual's personal taste, favored position arrived at only after a lot of flying/testing? If you can agree to that, would you also think that this position the plane manf. supplies might be towards the front of the "range" generally flown?
I agree many thing are subjective, and I'd also agree the larger RC stuff has the potential for much higher power to weight ratios, allowing them some advantage. The rest of your comments I struggle with.
The thing is, named maneuvers, when flown by a "small" plane or a "big" plane, are the same. They are flown the same, and judged the same, big and small alike.There's no extra credit given for flying a maneuver well with a small plane, nor is there one expected.
Regarding "true" CG position given by a manf., it's pretty much fact many flying the same plane will have a range of positions they favor. So how is the "true" CG position you speak of arrived at? Or, could you instead be thinking of a position that might be a good place to start - to be tuned to an individual's personal taste, favored position arrived at only after a lot of flying/testing? If you can agree to that, would you also think that this position the plane manf. supplies might be towards the front of the "range" generally flown?
I agree many thing are subjective, and I'd also agree the larger RC stuff has the potential for much higher power to weight ratios, allowing them some advantage. The rest of your comments I struggle with.
03-26-2017, 06:45 AM
#17
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Most the replies are spot on... I'll touch a bit on setting up for a landing. As you know from being a full-scale pilot, once you set up your approach glide angle, you add/remove power not elevator to control that angle. Find the speed that allows the plane to descend in a flat glide but above stall speed. If your plane descent angle steepens, add a bit of power.
I fly from a rather short paved runway with trees that need to be cleared on approach. Any glide angle over about 20 degrees will build up too much speed on my larger planes. Flying just above stall I can drop it into the first few feet of the runway consistently by blipping the throttle as needed.
I find that almost every plane's suggested CG is way forward from ideal. Many of my planes are perfectly stable with the CG sometimes an inch back from recommended. I slowly move the CG back until it wants to climb inverted than remove a bit so it is pitch neutral both upright and inverted.
Get to know your planes stall characteristics a couple of mistakes high. This will be time well spent.
I fly from a rather short paved runway with trees that need to be cleared on approach. Any glide angle over about 20 degrees will build up too much speed on my larger planes. Flying just above stall I can drop it into the first few feet of the runway consistently by blipping the throttle as needed.
I find that almost every plane's suggested CG is way forward from ideal. Many of my planes are perfectly stable with the CG sometimes an inch back from recommended. I slowly move the CG back until it wants to climb inverted than remove a bit so it is pitch neutral both upright and inverted.
Get to know your planes stall characteristics a couple of mistakes high. This will be time well spent.
Last edited by warhwk; 03-26-2017 at 06:48 AM.
03-26-2017, 09:27 AM
#18
I find that almost every plane's suggested CG is way forward from ideal. Many of my planes are perfectly stable with the CG sometimes an inch back from recommended. I slowly move the CG back until it wants to climb inverted than remove a bit so it is pitch neutral both upright and inverted.
Get to know your planes stall characteristics a couple of mistakes high. This will be time well spent.
Get to know your planes stall characteristics a couple of mistakes high. This will be time well spent.
03-26-2017, 05:10 PM
#19
My Feedback: (2)
A lot of guys push that nose high, use the throttle to control altitude type approach because they've learned how to do it number one. But number two is likely because it gives you so much more control over your landing, including that landing's position on the runway. A well executed landing using this method is a thing of beauty!
However, I believe it's well beyond the capabilities of a lot of guys that haven't been playing with that approach. It's not frequently taught any more. I think it might be because many rookies view a landing as a necessary evil - not a thing of potential total grace. They set their planes up in a glide that ends at touch down, possibly easing the plane on to the ground in the flair with a few extra rpm's. IMHO, there's nothing wrong with a landing like that. I've seen guys fly those for their entire flying career, often spanning MANY years!
I fly both ways, powered approaches and glides. Many of my landings are started in a glide, and as I like to mess with 3D, often the approach flown using throttle to control altitude is stretched out, flown to extremes - possibly at speeds not much over a walking speed - and may extend into a tour around the field! Flying the right plane set up properly for this type flying (high alpha) is a real excersize in control - as you are going to be flying/correctling on all axis, as well as the throttle..... a blast!
Anyway, my point here is there's nothing wrong with using a glide to land your plane. Yes, there are ways to make it "prettier", but there's no "must learn" involved. I will say that bigger stuff does use a lot less runway in one of those throttle controlled descents.
Another full scale pilot.... -Al
However, I believe it's well beyond the capabilities of a lot of guys that haven't been playing with that approach. It's not frequently taught any more. I think it might be because many rookies view a landing as a necessary evil - not a thing of potential total grace. They set their planes up in a glide that ends at touch down, possibly easing the plane on to the ground in the flair with a few extra rpm's. IMHO, there's nothing wrong with a landing like that. I've seen guys fly those for their entire flying career, often spanning MANY years!
I fly both ways, powered approaches and glides. Many of my landings are started in a glide, and as I like to mess with 3D, often the approach flown using throttle to control altitude is stretched out, flown to extremes - possibly at speeds not much over a walking speed - and may extend into a tour around the field! Flying the right plane set up properly for this type flying (high alpha) is a real excersize in control - as you are going to be flying/correctling on all axis, as well as the throttle..... a blast!
Anyway, my point here is there's nothing wrong with using a glide to land your plane. Yes, there are ways to make it "prettier", but there's no "must learn" involved. I will say that bigger stuff does use a lot less runway in one of those throttle controlled descents.
Another full scale pilot.... -Al
Last edited by ahicks; 03-26-2017 at 05:12 PM.
03-27-2017, 03:02 AM
#20
I have seen those indoor aerobatic competitions too but they don't use gas engines, do they? Here the topic was "Help, I cannot fly my first gasser.." in the first place.
Actually I was standing by the thought that compares two pilots to whom the same plane flies like a trainer or a warbird (pardon for naming "rocks" the tough planes by the way) depending on their skills.
Probably this innocent Sbach 342 in the hands of another buddy would be just flawless.
Besides, if anyone here had said: "Check your CG position and make sure the plane is not too heavy, then have a buddy help you set the plane up, regardless his/her age", would it have been of a struggle to the others?
Actually I was standing by the thought that compares two pilots to whom the same plane flies like a trainer or a warbird (pardon for naming "rocks" the tough planes by the way) depending on their skills.
Probably this innocent Sbach 342 in the hands of another buddy would be just flawless.
Besides, if anyone here had said: "Check your CG position and make sure the plane is not too heavy, then have a buddy help you set the plane up, regardless his/her age", would it have been of a struggle to the others?
Last edited by PiccoLino; 03-27-2017 at 03:13 AM. Reason: typing mistake
06-25-2017, 11:36 AM
#22
Thread Starter
Sorry for the delayed response 3 months later but i verified my CG was WAY off and the plane was far too nose heavy. This resulted in an aircraft i could not slow down and stalled hard as soon as you put the nose up. I crashed this plane 3 times thinking i couldn't go wrong with a nose heavy plane and kept adding weight thinking the flight characteristics were going to get better. NOPE... they progressively go worse until the last flight where it stalled on approach to landing. I finally rebuilt and flew the bird with the CG behind the wing tube as the manufacturer stamped on the aircraft. Voila... slows down nicely and i am able to hold a gentle nose high attitude after my roundout. The plane settles nicely onto the runway without any abrupt stalling. Thank you so much to everyone for all the commentary/suggestions. Those of you suspected the CG was off... YOU WERE RIGHT!!!
