FTFC20 Bellanca Aircruiser C-27A by Matagami Designs

[Matagami Designs]

Well just about finished the wing and realized....

....😒🤬

I guess I'll pick it up again tomorrow.

 

[willsonman]

Can't wait to see it at the field!

 

[Matagami Designs]

Getting closer... definitely looking like an aircruiser now. 👍

 

[Matagami Designs]

Wing is attached and all the control surfaces finished. I think I want to redo the wheel pants as I dont like the angle they will sit at and will take on alot of grass at the rear on landing. I need to figure out how to print it well enough with the bottom being curved around the wheel...

 

[Matagami Designs]

New wheel pants designed and got the left side printed. A bit rough on the steep rear overhang but might experiment with some fillers? Any suggestions. Went one wall thinner and will save 11 grams each. Chopped a bit of height off too. And my new wheels showed up! Printing the other side now.

 

[Matagami Designs]

Just about ready to maiden. 🤞😬🤞

 

[Aviator08]

Just about ready to maiden. 🤞😬🤞

Well, vrs 1 flew really well, so I expect this will be the same.

 

[Matagami Designs]

Well, vrs 1 flew really well, so I expect this will be the same.

Well maybe if I was a better pilot. It was a bit gusty today and took off fine. Needed a bit of trim in the elevator and I throttled back to do it. Was starting my second turn as i was going with the wind and stalled the inside wing and wasnt able to to recover from the spin. The wing is more similar to nerdnic's speed wings at this point so the tips aren't undercamberd. I also had too much elevator authority and no expo setup. 😐 I think this is kinda why I got into trouble. The front end and right wheel pant needs replaced but other than that I think it's ok.

 

[chris398mx]

Well maybe if I was a better pilot. It was a bit gusty today and took off fine. Needed a bit of trim in the elevator and I throttled back to do it. Was starting my second turn as i was going with the wind and stalled the inside wing and wasnt able to to recover from the spin. The wing is more similar to nerdnic's speed wings at this point so the tips aren't undercamberd. I also had too much elevator authority and no expo setup. 😐 I think this is kinda why I got into trouble. The front end and right wheel pant needs replaced but other than that I think it's ok.
View attachment 181330

Sorry to see! This plane design is really taking shape!! I am sure you will get it flying as it should!!

 

[Matagami Designs]

@willsonman I kind of wonder if the left aileron bugged out? I'm looking at it now and its angled down. like trying to roll to the right which is what was happening. Seems a little fishy as you would think these would have returned to center?

 

[willsonman]

They should have. Try going over the servo with a tester. Check your return to center as well. Lousy centering is usually due to a poor potentiometer. It also depends on the quality of the servo so check a known good or brand new one for reference.

 

[Matagami Designs]

Ready to try again. Hopefully with better results this time. I didn't notice anything when messing around with the servos so I guess i may have bumped it when putting it in my car.

 

[Matagami Designs]

Well I didn't have to much luck flying today. The 1st flight my elevator trim was way off again and had a rough "landing" after retrieving it I adjusted the elevator and tried again and this time had some success but only for a little while at speed. When I tried to slow it down it became unstable and I wasnt able to manage a good enough landing to make any more flights. Not sure what to do with this design at this point. I'm wondering if I have made it too heavy about 50 oz on a 50 inch wingspan. About 375 square inches on the main wing. The original version was a good bit lighter. Only 35 oz or so. I am also continuing to question if going back to the ft style airfoil would really make it much more stable or if there is some other factors at play. I am fairly sure I could shed weight by using that style airfoil though. And time to build is better as well. I am also wondering do I need to put the differential ailerons back. It would be easy to do with a mix at this point. Do I start over trying to shed some weight and make things simpler or keep fighting this design?

 

[Flitedesign 3d]

Well I didn't have to much luck flying today. The 1st flight my elevator trim was way off again and had a rough "landing" after retrieving it I adjusted the elevator and tried again and this time had some success but only for a little while at speed. When I tried to slow it down it became unstable and I wasnt able to manage a good enough landing to make any more flights. Not sure what to do with this design at this point. I'm wondering if I have made it too heavy about 50 oz on a 50 inch wingspan. About 375 square inches on the main wing. The original version was a good bit lighter. Only 35 oz or so. I am also continuing to question if going back to the ft style airfoil would really make it much more stable or if there is some other factors at play. I am fairly sure I could shed weight by using that style airfoil though. And time to build is better as well. I am also wondering do I need to put the differential ailerons back. It would be easy to do with a mix at this point. Do I start over trying to shed some weight and make things simpler or keep fighting this design? View attachment 181613

Sorry to hear you have little succes with this design, it looks really good on the outside. I would definitely aim for a plane as light as possible, weight makes often most of the difference in the flight performance. Especially because you said it flew fine as long as you had speed. How is this so much heavier thant the one before? Are you using some heavy foam board?

 

[Matagami Designs]

Sorry to hear you have little succes with this design, it looks really good on the outside. I would definitely aim for a plane as light as possible, weight makes often most of the difference in the flight performance. Especially because you said it flew fine as long as you had speed. How is this so much heavier thant the one before? Are you using some heavy foam board?

This new version has a bigger motor, and esc, reinforced the main wing and stub wing with basswood spars, printed wheel pants, 2 extra servos for flaps... the foam is the same. Hard to believe its that much heavier but I guess with all the "enhancements" and extra glue the weight is a bit out of check.

 

[Aviator08]

This new version has a bigger motor, and esc, reinforced the main wing and stub wing with basswood spars, printed wheel pants, 2 extra servos for flaps... the foam is the same. Hard to believe its that much heavier but I guess with all the "enhancements" and extra glue the weight is a bit out of check.

I'm also sorry to hear that.... The vrs 1.5 that I built flew so good that I gave it to a student that is doing well with his flying. It flew very much like a trainer. The weight to wingspan shouldn't be too much. The wing airfoil may have something to do with it. Might want to use the standard FT style for stability. Did you use the flaps for landing? Was it squirrely in the air? If you want to send me the latest files, I will build one and see what I come up with. It is too good-looking of an aircraft not to have it flying well.

 

[willsonman]

Wing loading is still quite good at around 19oz/ft^2 and a cube loading of around 12. I think it would be interesting to build a prototype with only FLAT plate struts, no airfoil, and again with only struts (skewers) and no wing area for the landing gear. I think that will be a bit telling here. It may be an issue with conflicting angles of attack between the top wing and the gear struts.

The basic Bernoulli principle indicates that air is accelerated over the top of the wing. Well, if it is accelerating over the top of the struts there is a LOT of wing area on the bottom of the TOP wing that may be seeing some conflicting accelerated air giving a false sense of instability. Remember AIR DOES NOT SCALE so it may be that this design will work at a much larger scale as-is. This may turn out to be the compromise you have to make for a model. Some of the other racing airplanes from this era end up having an increase in tail area for stability because of this same issue.

 

[Matagami Designs]

Wing loading is still quite good at around 19oz/ft^2 and a cube loading of around 12. I think it would be interesting to build a prototype with only FLAT plate struts, no airfoil, and again with only struts (skewers) and no wing area for the landing gear. I think that will be a bit telling here. It may be an issue with conflicting angles of attack between the top wing and the gear struts.

The basic Bernoulli principle indicates that air is accelerated over the top of the wing. Well, if it is accelerating over the top of the struts there is a LOT of wing area on the bottom of the TOP wing that may be seeing some conflicting accelerated air giving a false sense of instability. Remember AIR DOES NOT SCALE so it may be that this design will work at a much larger scale as-is. This may turn out to be the compromise you have to make for a model. Some of the other racing airplanes from this era end up having an increase in tail area for stability because of this same issue.

Would it be any better to have a symmetric airfoil on the bottom in place of the flat bottom airfoil? I would hate to have to get rid of the element that makes this so iconic. I'm not really sure I fully understand what you mean by saying air dosent scale? Would you make both the vertical and horizontal bigger?

 

[Matagami Designs]

I'm also sorry to hear that.... The vrs 1.5 that I built flew so good that I gave it to a student that is doing well with his flying. It flew very much like a trainer. The weight to wingspan shouldn't be too much. The wing airfoil may have something to do with it. Might want to use the standard FT style for stability. Did you use the flaps for landing? Was it squirrely in the air? If you want to send me the latest files, I will build one and see what I come up with. It is too good-looking of an aircraft not to have it flying well.

I started working on the next version after the remaiden failed going back to the standard FT airfoil. I was going to do full length flaperons too but decided to take a break to build a might mini nemesis to have some fun. I was about finished just wanted to redo the stub wings to eliminate the need to do all the chamfering and sanding. Once I update that I will send you V4 if you would like make another attempt. I tied maybe 20 degrees flaps but as the speed came down the nose dropped harshly and felt pretty uncontrollable from there. At speed I could control it somewhat.

 

[willsonman]

Would it be any better to have a symmetric airfoil on the bottom in place of the flat bottom airfoil? I would hate to have to get rid of the element that makes this so iconic. I'm not really sure I fully understand what you mean by saying air dosent scale? Would you make both the vertical and horizontal bigger?

Tail areas also seem fine using the TLAR method.

Air does not scale: The density and viscosity of air does not change whether you are using a full-scale or 1/16 scale airplane. The thought is that if you use the same aerodynamic features then generally they will fly the same. However, there are still size constraints because of the physical size of the volume of air. For your wheel struts, you have these struts that have an airfoil. The air going over the top is accelerated per standard principles of aerodynamics. Now, the length at which that accelerated air extends away from the top surface of the strut is determined by your chord thickness. To add a bit of insult to injury, the extreme dihedral of the struts allows for the air extension perpendicular to the upper surface to conflict more with the two different panels and will create a larger pocket of turbulent air... all under the main portion of the wing. If you are creating turbulent or accelerated pockets of air under the top wing (and a vast % of it at that) you are likely to get a lot of issues with pitch control that may be perceived as a CG issue.

It may be that you are seeing OK evenness of lift at one angle of attack of the wing/struts but when you change pitch, roll, or yaw the angle of attack along with variation of span-wise flow of air is going to disturb the air on the bottom of the top wing.

Another way of looking at this section is to think of it as an annular wing. Annular wings almost always have constant chord length. The intersection of the strut and the main wing is an instance of change in chord length where the flow of air is creating an area of the top wing that is becoming ineffective.

I'm not an expert on these things. Perhaps @Mid7night may have some thoughts on this more but it is an interesting subject of discussion/debate. The fact remains that it's such a good-looking model that it should not be left to the wayside.