Nosediving FF Kit

[sidnb]

Hi,

When attempting to trim the 2019 FF kit, I glided the aircraft with the prop and RB attached without any winds. Despite moving the ballast weight of 0.5g backwards to compensate for nosediving, the aircraft still nosedives at a roughly 20 degree incline over 15 feet. If this helps, the diameter of turn for the aircraft is roughly 25 feet. Thanks.

[bjt4888]

Sidmb,

Congratulations on completing a FF kit airplane. Once trimmed, it should be very competitive.

It is never necessary or advisable to glide test an indoor rubber powered airplane. If you have built all the trim settings into the airplane per the very detailed instructions, begin test flights following the instructions that start on page 14. Pay special attention to the “winding” and “torque meter” sections of the instructions.

There is comprehensive information that I posted and other experienced students and coaches posted about winding and test flying in this wiki in the 2015 archive. If you read this info, you will advance rapidly in you understanding of how to fly championship flight times.

Brian T

[arshah2]

I also have built a freedom flight kit, and am getting very competitive times with it.

I would suggest trying to increase the angle of incidence of your wing before changing your center of gravity. Another problem could be that your horizontal stabilizer is at too high of an angle of incidence. Changing the center of gravity without knowing the planes true attitude will have no real effect, except to make your plane heavier. I would suggest checking your center of gravity by balancing the plane on a pencil with the rubber and prop attached. If it is between 2.5 to 3.5 inches behind the trailing edge, the backside, of the front wing, then you do not need to change it yet. Also, make sure that your propeller is attached to the same axis as the motor stick (not tilted up or down).

Hope this helps,

arshah2

[sidnb]

Hello,

Thank you for the helpful responses. I took arshah2's advice on the wing positioning and used the thinnest rubber band available with the kit (0.087 in), which was cut to weigh roughly 1.8 g. This RB width offerred the best time for my plane. With about 120 winds forward and 5 backwards on the 15:1 winder, I was able to achieve a flight time of 2:17. I have attached a link to a video which covers most of the flight in my school's orchestra room which has a height of between 21 and 24 feet. The flight ended with many winds left on the rubber band. I am thinking about making a lighter rubber band in order to maximize efficiency; would this be the right approach to take?

https://drive.google.com/file/d/1AfdicG ... sp=sharing

Thanks,

sidnb

[klastyioer]

Hello,

Thank you for the helpful responses. I took arshah2's advice on the wing positioning and used the thinnest rubber band available with the kit (0.087 in), which was cut to weigh roughly 1.8 g. This RB width offerred the best time for my plane. With about 120 winds forward and 5 backwards on the 15:1 winder, I was able to achieve a flight time of 2:17. I have attached a link to a video which covers most of the flight in my school's orchestra room which has a height of between 21 and 24 feet. The flight ended with many winds left on the rubber band. I am thinking about making a lighter rubber band in order to maximize efficiency; would this be the right approach to take?

https://drive.google.com/file/d/1AfdicG ... sp=sharing

Thanks,

sidnb

lol same goes to you, i know you want help but if u ever want to any one specific, dm them videos cause now everyone on the internet can see this. but ill take a look at this vid and try to give you some advice

best of luck!

[klastyioer]

Hello,

Thank you for the helpful responses. I took arshah2's advice on the wing positioning and used the thinnest rubber band available with the kit (0.087 in), which was cut to weigh roughly 1.8 g. This RB width offerred the best time for my plane. With about 120 winds forward and 5 backwards on the 15:1 winder, I was able to achieve a flight time of 2:17. I have attached a link to a video which covers most of the flight in my school's orchestra room which has a height of between 21 and 24 feet. The flight ended with many winds left on the rubber band. I am thinking about making a lighter rubber band in order to maximize efficiency; would this be the right approach to take?

https://drive.google.com/file/d/1AfdicG ... sp=sharing

Thanks,

sidnb

lol same goes to you, i know you want help but if u ever want to any one specific, dm them videos cause now everyone on the internet can see this. but ill take a look at this vid and try to give you some advice

best of luck!

okay so something i see right off the bat is that your circle is a tad tight. if thats what your aiming for meaning like itll benefit you in future competitions, go for it. if you have a fairly large gym or place that you will be flying at to compete in the near future, you might wanna decrease the tilt in that stabilizer. itll aim a slowly climb which will hopefully boost your time. your cruise is really nice, but it goes through winds a bit fast, which i mean isnt a huge issue but if you choose to fix that later, ill try to help as well. it seems to be wobbling side to side or up and down, cant really tell to be honest with you. if its side to side wobble, its probably uneven weight distribution. what i found when i was making my plane is that you rly cant screw up the weights cause the wing and stabilizer sizes are almost identical so any flaw will throw it off. if its up and down, its probably stall which means you have too much lift and you should bring the front wing post down. if its the vents, nothing you can do about it. you also seem to have a few d winds or left over winds after that. what that tells me is your lift has a ton of power and it gets up there super early, cruises, and comes down with too many winds since it was an early climax. you could honestly try lighter rubber, i think it would benefit, but make sure to keep that video and record in your flight log for that flight. its important to also take pictures of your wing posts so that you remember where they are. cause if you try something new and its a total failure, you have to know where to pick back up. but yeah def try different rubbers once you think you have a good build because thats like a rly big part of this event and will most likely lead to your success.

[coachchuckaahs]

I agree, the circle is a bit tight. If you open up the circle some, you will need to re trim the flight, but it should help.

I see a bit of dutch roll. You may need more vertical fin area.

The let down does not look all that fast. As the rubber unwinds, the torque goes down substantially leading to letdown. Measure the actual turns left on the motor. You will likely have similar turns remaining as what you took off on the unwind, if the rubber is matched to the prop. It seems like you are leaving a lot of winds on the table, but there is not a lot of energy in those winds. If a lot, then thicker rubber may help, but will need more unwinds up front.

Coach Chuck

[fifty_missions]

If you go back to the original issue of test gliding without winds... yes a good idea but without the prop assembly. Why? Big, giant air brake, no surprise it dove.

Instead, weigh your prop assembly and make a wad of artist's clay the same weight. Stick that on the nose instead of the prop assembly and give the model a glide. Be sure to launch slightly nose down otherwise you will induce a stall.

Good Luck,
50 Missions

[klastyioer]

at soup i saw quite a few ff kits doing the dutch roll thing
idk if it was the vents or not but all of them had the same rudder
soooo any ideas as to why this is happening?

[Rossyspsce]

at soup i saw quite a few ff kits doing the dutch roll thing
idk if it was the vents or not but all of them had the same rudder
soooo any ideas as to why this is happening?

What is Dutch roll