Instructions for building plane without kit?

[calgoddard]

For those wishing to compare the performance of 2015 WS models with 2017 WS models, here is a summary of the salient specs for the 2015 Division C Wright Stuff event:

monoplane

wing - 50 cm max x 8 cm max

stab - 30 cm max x 6 cm max

minimum airplane weight - 8 grams

max prop diameter - 24 cm

max rubber weight - 2 grams

The wing loading for 2015 was 0.020 grams per square centimeter

The wing loading for 2017 is 0.015 grams per square centimeter

The significantly higher wing loading under the 2015 WS rules was offset by 33% more rubber motor and a larger prop.

Under the 2015 WS rules there was a 10% bonus at State for a wing having a chord that did not exceed 7 cm.

[Kyle_Guo]

Kyle,

I'm going to reply again to encourage you; and push you a little. You're doing very good work on a difficult project and I congratulate you. You may already be doing this, but if not, I want you to consider converting my posts or recommendations in to lists of items to complete. When you complete an item that I recommend, check it off the list. If you are not understanding an item, be sure to ask a question right away.

It is likely that inadequate left wing washin is causing the airplane to roll quickly to the floor. Also, you will note in the Freedom Flight kit and in the Finny 09 plan that there is left wing offset. Both of these settings are critical. Since you don't mention checking the stabilizer incidence, I mentioned again above.

The likely reason that the airplane flew a little when you moved the wing forward again, is that this adjustment made the nose of the airplane very very light (CG way too far back) which would result in such an extreme "nose-up" capability that the lack of roll control (inadequate left wing washin and offset possibly) becomes insignificant to the ability to fly for a short duration. With this type of setup, a very short flight would result in a large stall (which is deceptive to observe since the airplane is under full power) and a quick landing.

Also, you mention launching at 1,800 turns. If left wing washin and offset and wing/stabilizer decalage angles are correct, as well as correct propeller thrust line offset, stabilizer tilt and tailboom offset, it should only take about 1,000 turns on a 1/16" motor to give you a good first test flight. 1,800 is too much for the first flight. After the first test flight has demonstrated that the setup is safe (smooth 25 ft diameter climbing circles followed by smooth descending circles to about 15 ft height) you should be winding to about 85% maximum turns, which is about 2,200 or 2,300 turns for 1/16" rubber, and about 1.1 in oz torque and backing off turns, maybe backoff about 180, till torque reduces to 0.30 in oz torque for your next flight (as I already mentioned in an earlier post).

Brian T.

As I understand, left wing wash-in is when the angle of attack is greater on the left side of the wing than the right so the plane stays level. I do not understand how that is made. I realize that the wing naturally warps a bit but how do you control how and where it warps? The only way I think you can make the left wing wash-in increase is if you put a diagonal support on the wing, holding the left wing higher while the support on the back keeps the TE at the same height. The Wing/decalage angles are not correct. My stab has a positive incidence because in the FF kit they specified to put a shim under the LE of the stab. Should I remove the shim? Also the prop is set at 3 degrees left thrust and the stab tilt is not exagerated. The tailboom offset is also 3 degrees. I normally use 0.065" motors and I do not have 1/16 (0.062"). I do not understand how when I wind 1800 winds there is 0.35 in-oz torque and that doesn't get the plane near the ceiling. If that is 2200-2300 turns for 1/16 rubber, it must be less for 0.065 rubber. Possibly 1900-2000 turns? If you back off to 0.30 in-oz, it will not climb very much for my plane. I feel that I need a very high torque in order to get near the ceiling but that much torque may not be possible with 1/16 rubber.

[bernard]

Kyle, does the Freedom Flight kit really instruct you to put the shim under the stabilizer? Washin in the left wing is built in with a shim. A warped stabilizer is not good for plane stability. If the built in washin is not enough, more can be added by very, very carefully bending either the leading or trailing edge of the wing or attaching a thin thread with tension connecting one leading or trailing edge tip to the mounting post of the wing.

[bjt4888]

Kyle,

Let's start by getting more information. I believe that I understand from your previous posts that you now have the wing LE 4.5" back from the nose and the CG is at 1.5" from the sing TE. If this is not correct, please reply with these measurements.

Now please describe your 50 second flight. How many turns did you put in? What was the torque reading with these turns? Was this with the .065" rubber? How long was the rubber loop you used for this flight? What does it weigh? Does the weight include two black rubber o-rings? Did you backoff any turns before launch? If so, how many and what was the resulting launch torque? Describe the character of this flight. Here's an example of a good description of the character of a flight you might have experienced: launched 3 ft from the floor, climbed in 25 ft diameter circles, climb was smooth and not excessively banked, no noticeable stalling during the climb, climbed to 6 ft from the floor in the first circle, reached 12 ft from the floor in a total of three circles, and flight duration at this point was 30 seconds, began descending from this point and descended in three circles to land at 50 seconds, no noticeable stalling during descent. Describe your actual flight in this manner as best as you can remember.

Did you remove the motor at the end of the flight and record the remaining turns?

A 1.5 gram motor (weighed with two black rubber o-rings) of .0625" or .065" rubber can be wound to at least 1.4 in oz before it breaks. I may have misquoted or averaged the turn capability of the rubber previously. A 1.5 gram (actually 1.42 gram as the o-rings weigh .08 grams per pair) .065" motor (which is about .043 g/in) will probably take about 2,560 turns before breaking and can safely take 90% of these turns, or about 2,295 turns for SO competition.

Let's discuss rubber, winding, decalage angle and left wing washout after you supply the info in my questions above.

Brian T.

[Kyle_Guo]

Kyle, does the Freedom Flight kit really instruct you to put the shim under the stabilizer? Washin in the left wing is built in with a shim. A warped stabilizer is not good for plane stability. If the built in washin is not enough, more can be added by very, very carefully bending either the leading or trailing edge of the wing or attaching a thin thread with tension connecting one leading or trailing edge tip to the mounting post of the wing.

Yes, There is a 1/16 thick tiny piece they instruct you to put under the LE of the horizontal stab before you glue that to the CF rod at desired angle. It just raises the horizontal stab a minuscule amount and I'm not sure if it is needed. It's not warped, the CF that makes up the horizontal stab is stiff and won't warp easily, it just raises the incidence. I didn't remember the Kit telling me to put any shims on the wing at all.

As for your comment, Brian, I need some time to compile the information and I will reply as soon as possible

[Kyle_Guo]

Kyle,

Let's start by getting more information. I believe that I understand from your previous posts that you now have the wing LE 4.5" back from the nose and the CG is at 1.5" from the sing TE. If this is not correct, please reply with these measurements.

Now please describe your 50 second flight. How many turns did you put in? What was the torque reading with these turns? Was this with the .065" rubber? How long was the rubber loop you used for this flight? What does it weigh? Does the weight include two black rubber o-rings? Did you backoff any turns before launch? If so, how many and what was the resulting launch torque? Describe the character of this flight. Here's an example of a good description of the character of a flight you might have experienced: launched 3 ft from the floor, climbed in 25 ft diameter circles, climb was smooth and not excessively banked, no noticeable stalling during the climb, climbed to 6 ft from the floor in the first circle, reached 12 ft from the floor in a total of three circles, and flight duration at this point was 30 seconds, began descending from this point and descended in three circles to land at 50 seconds, no noticeable stalling during descent. Describe your actual flight in this manner as best as you can remember.

Did you remove the motor at the end of the flight and record the remaining turns?

A 1.5 gram motor (weighed with two black rubber o-rings) of .0625" or .065" rubber can be wound to at least 1.4 in oz before it breaks. I may have misquoted or averaged the turn capability of the rubber previously. A 1.5 gram (actually 1.42 gram as the o-rings weigh .08 grams per pair) .065" motor (which is about .043 g/in) will probably take about 2,560 turns before breaking and can safely take 90% of these turns, or about 2,295 turns for SO competition.

Let's discuss rubber, winding, decalage angle and left wing washout after you supply the info in my questions above.

Brian T.

The LE is 4 5/8" back, and the CG is 1/2" front the TE. I can adjust the CG by shifting the clay (which is at 1/2" front of TE because whenever I moved it to the front to make it 1.5", the plane would dive and I would get single digit times, due to inadequate wash-in probably) My 50-second flight was not exactly the best it could have been. It climbed slowly with very slight stalls from about 4 feet in a light push until about 15 or so feet (took maybe 2-3 turns) and then I had a small turn circle (10-20 feet diameter) The turns resulted in small erratic shifts in directions instead of a smooth transition (maybe a 20 degree shift each time?) probably because the turn was too small. The plane stayed at that height, refusing to climb higher. Towards 2/3 way done, the stalling was worse and the plane slowly dropped and dropped until it grasped the ground and the plane stopped (in 4-6 turns) I put in 1400 turns and the torque reading was 0.30-0.32 in-oz. This was with 0.065 rubber. The rubber loop was 18"-18 1/2" in relaxed state and It weighed 1.48g- 1.49g (the scale read it differently many times, didn't know which was the right weight) I had only 1 O-ring because I could hook it without it and it was a waste of weight in my opinion. I did not back off any turns because my plane will probably never be at the 20 feet height it should cruise at. I cannot remember the exact turns but It probably got 2 feet from each turn and got up to 10-15 feet, then slowly went down with each stall bringing it 1-2 ft closer to the ground. I didn't know the exact amount of turns because it's hard for me to count turns accurately but im thinking I only used half of my winds because A LOT of winds were left. Enough for another flight that will be shorter because of less torque. I didn't know it could be wound that high becuase when I wind it never exceeds 0.40 in-oz. I guess I used old bands because when I tried to break them, they broke at 0.4 in-oz. I will be redo-ing a test to break a loop so I can better understand and use more of what the rubber can provide in order to get higher flights.

[bjt4888]

Kyle,

Very good information. Diagnosing will be challenging via wiki. If i could handle the airplane we would have it figured out in five minutes. I need a few more bits of info.

What is the wing incidence? Give me the length of the front wing post from top edge of motor stick to bottom of LE and the length of the rear wing post from top edge of motor stick to bottom edge of TE. Make these measurements with the wing posts pushed into the tubes the same distance as when you were flying it.

When you mentioned in an earlier post that you shimmed the stabilizer LE, what do you mean? Describe exactly. It looks from the picture you posted that the stabilizer is attached below the carbon rod (tube?) tailboom. If this is true, then are you saying that there is a shim between the top edge of the stabilizer LE and the tailboom? If so, how thick is the shim?

Brian T.

[Kyle_Guo]

Kyle,

Very good information. Diagnosing will be challenging via wiki. If i could handle the airplane we would have it figured out in five minutes. I need a few more bits of info.

What is the wing incidence? Give me the length of the front wing post from top edge of motor stick to bottom of LE and the length of the rear wing post from top edge of motor stick to bottom edge of TE. Make these measurements with the wing posts pushed into the tubes the same distance as when you were flying it.

When you mentioned in an earlier post that you shimmed the stabilizer LE, what do you mean? Describe exactly. It looks from the picture you posted that the stabilizer is attached below the carbon rod (tube?) tailboom. If this is true, then are you saying that there is a shim between the top edge of the stabilizer LE and the tailboom? If so, how thick is the shim?

Brian T.

The measurement for the amount of penetration for LE post from the top of the MS is 3/16" and the length of the TE post penetration is 5/16". The length of both posts are 2 6/16". I mean. there is a main CF rod that serves as the tail boom. The horizontal stabilizer is glued onto the rod with a 1/16 thick tiny shim piece put under the leading edge, raising it a little. Yes. The shim is put under the LE, glued to both the rod and the stab so that the LE is raised by how tall the shim is (1/16") Does this mean I have to increase the incidence by 1/16" in the wing to compensate for the incidence in the stab?

Should I make a video of a flight with 1400 winds in the current condition and post it here? I can test on Tuesday and make the video and post it on Tuesday night. That may help you. I'll also add more defined pictures so you can observe the plane itself.

[bjt4888]

Kyle,

A video of a flight would help. I think that I will need to take pictures of one of my airplanes to help communicate the wing incidence measurement. I am not sure, but I think that you are communicating that the wing incidence is zero degrees (both wing posts the same length as measured per my last post description.

I see that you have posted questions about solving your winding issues. You must solve the incidence, decalage, CG and washout issues before anything can be done related to winding issues.

Brian T

[Kyle_Guo]

No, I'm saying that the posts are the same length, but they penetrate into the plastic tubing to different lengths. I stated the penetration length into the tubing. Just subtract that from the post length and you get the length over the MS.(not in the tubing)