Flight B/C

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WetUnicorn
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Re: Flight B/C

Post by WetUnicorn »

Hi, I’ve been reading all the posts in this thread, and thank you so much pumptato-cat and everyone else for posting so many questions!! They really help especially when all the coaches post their answers! This is also my first forum post so sorry that 1. Its long and 2. I probably forgot a bunch of stuff i wanted to ask…

I’ve got a FF kit, and i had a question about my CG/ballast placement. Here are my current plane settings first: got 1.26g of total ballast and instructions say all at the nose but i got 0.55g at nose and 0.71 g 4 1/8" (~10.5cm) from the back of the plane. Is this optimal? Cg is at 2 1/8" back from te, and wing position is 1/4" behind the kit recommendations. Front wing post/le is raised 3mm up for incidence. Prop pitch hasnt been changed (idk how to change anyways). Left wing washin i want to say is about 1/8" but i dont know if im doing it right…It flew at the birds invitational for about 1;30 mins, so i want to say it is reasonably trimmed. My question though, is that is it ok to have clay at the nose and clay towards the back of the plane? How will it affect my plane performance? Also what is the reason for putting all the clay at the nose? I haven’t tried moving the clay yet because i just got done with the invitational and i didnt want to change any settings in case it messed up my plane. I also don’t get a lot of gym practice (like 30mins a week) and I dont want to waste time experimenting with ballast/CG because what I have works (i mean at least right now thats what I want to know). I think my next step in trimming should be putting more winds in, I haven’t been winding to max and backing off as I should (discovery requires experimentation) and I think also trying different rubber and stuff but I just wanted to confirm the trim settings I have now aren’t going to haunt me later :) . I do have a video if it helps…

Also Josh Finn i know you come into these posts a couple of times, and I’ve got a personal question for you: How on earth do you do test/trim flights in your house/living room?!!?!?!?!!!! I tried doing that with the Guru plane (which yes i figured out sucks) and it broke like 5 different times. I’ve watched your youtube videos and seriously i cant figure it out!! How do your planes NOT totally break?! Just wondering :)

Also another question (sorry) but what are anyone’s opinions on flying outside? Like i said, I dont get a lot of gym time and there is literally no where else for me to fly (even a classroom) except my own house. So I’ve resorted to flying outside and thats where i get a lot of my data for my flight logs. Just wanted to ask how reliable is this/is it a good idea? I know lots of external factors (like wind arghh) and really influence how the plane flies and stuff, but just wondering. Thank you so much anyone willing to help me out here…and also to everyone who has already posted!!
Last edited by WetUnicorn on January 31st, 2023, 8:57 pm, edited 1 time in total.
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Re: Flight B/C

Post by bjt4888 »

danxmemes wrote: January 31st, 2023, 5:47 pm I'm back after flying today, and I see some very interesting issues that I have no clue about how to fix.

I have fixed the stalling, and for the most part, the plane flies like how it should fly, except it does not get nearly the times I used to get with the rubber. Before, I was able to get high 2 minutes with the Div B plane, but now its barely two minutes. Number of winds on motor remain the same, about 1250, and launching torque, ceiling height, and winds remaining remain the same, at about 300. Why does the flights run out of rubber much quicker and come down much quicker than before? And how can I fix this?

Second thing, just kind of weird, is the way my lubricant is applied. This is the lubricant that I use: https://www.homedepot.com/p/Blaster-11- ... 529794-_-N

The interesting part is that whenever I directly spray it onto the rubber, all is fine, and I have tested this across over 10 rubbers. However, when I spray the lubricant into a bag and then do the same winding process, the rubber is significantly weaker and has a bunch of tears in it after only 2 winds. Just a weird thing that I wanted to share, but am I being superstitious or is there something else going on?

Main issue is still about the plane getting more time, any guidance is greatly appreciated. Thanks in advance!
Danx,

Looking at the SDS sheet (in the link you supplied), hydrotreated light distillate is a petroleum product. This does not look like good rubber motor lubricant. Try using Armor All “Original Formula”. This is available at almost any automotive shop and from other online sources. We have used this lubricant for years and can reliably wind a motor aggressively to 80-95% of breaking turns six to eight times with good flying characteristics.

If you supply your flight log showing the rubber density and winding details for the past good flights and the recent not as good flights, we can provide more assistance.

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Re: Flight B/C

Post by coachchuckaahs »

I agree with Coach Brian that your logged data is critical to understanding what changed to impact flight times.

It is critical to always record changes. We keep one (wide) column available for "notes" that cover anything that is not already logged in a dedicated column.

To your issue, if I read correctly you are using similar rubber loops with similar winding, but lost a substantial time by "fixing the stall". Well, the stopwatch does not lie! I am assuming you fixed the stall with a limited number of changes, so review those changes and move back toward the prior settings, searching for an optimum.

This year's plane, especially C, is highly sensitive to CG location, and to decalage settings. IN general indoor duration planes are optimized very close to stalling. So you may have seen some minor stalling, perhaps induced by air pockets, and tried to get rid of them by reducing decalage. This ends up with a plane the flies "flatter". It flies a little faster, which in turn makes the propeller spin faster, using up the winds faster. While such a flight may "look" smoother/better, it is in fact less optimal as your stopwatch indicates.

If indeed you are launching at similar torque and similar winds, and leaving the same winds at the end, this means your average RPM is higher. If also this is the same prop, then my conclusion would be the plane is flying too flat.

Increase decalage (or move CG back), undoing some of what you changed. Increase until a stall becomes noticeable, then decrease very slightly. This becomes a starting point. Now make multiple flights, changing the decalage perhaps 1/2 mm at a time to explore for an optimum on the stopwatch. Each flight condition should have the launch torque optimized to get the same peak altitude before comparing stopwatch times.

In general, the optimum may be more nose-high, or closer to stalling, than you may expect.

You may even want to add a column or two, "RPM", to your log. One could be the average, taken as the total revolutions used (launch winds minus winds remaining) divided by the time in minutes, while another could be teh cruise or letdown RPM, determined by measuring with another stopwatch, observing the plane for say 10 prop revolutions.

Coach Chuck
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danxmemes
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Re: Flight B/C

Post by danxmemes »

thank you! I do not have a good flight log, but I will be starting one asap. I do agree that it flies very flat, so I will be changing that. Again, thank you for all the help!
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Re: Flight B/C

Post by randomdogonapc »

I’m still having trouble making the flaring Ikara propeller. I’m looking at page 8 of the design forum from 2015, and it says to cut off half of the propeller blade from the spar. I’m not sure that that’s what I’m supposed to do, because it looks like if I cut my propeller from the spar, there would be very little material left. I’m also sure that I’m using an Ikara propeller. Could anyone send me a photo of their prop? Also, I’m not sure how I’m supposed to attach an image on this post, because it says that one image is too large of a file to attach. Thanks in advance.
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Re: Flight B/C

Post by bjt4888 »

randomdogonapc wrote: February 1st, 2023, 4:46 pm I’m still having trouble making the flaring Ikara propeller. I’m looking at page 8 of the design forum from 2015, and it says to cut off half of the propeller blade from the spar. I’m not sure that that’s what I’m supposed to do, because it looks like if I cut my propeller from the spar, there would be very little material left. I’m also sure that I’m using an Ikara propeller. Could anyone send me a photo of their prop? Also, I’m not sure how I’m supposed to attach an image on this post, because it says that one image is too large of a file to attach. Thanks in advance.
Random,

The Ikara prop you should be modifying is the wide bladed version. See these on the Freedom Flight Models website here: https://www.freedomflightmodels.com/props.php

You cut off the narrow portion of the blade leaving a 1.5” blade chord that can be sanded partly to about .001” thinner. I’ll post a Google drive link with a picture of a Wright Stuff airplane from 2016 that has this propeller type on it. You’ll see the sanding marks in this pic. Also, after trimming the blade (use a good steel straight edge and a sharp blade) you will need to twist the prop shafts to increase the propeller pitch to about 35 degrees (very important; 35 degrees as measured with the Freedom Flight pitch measuring tool which measures at the 2” blade radius) per the instructions in the Freedom Flight instructions.

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Re: Flight B/C

Post by bjt4888 »

Here is a folder with a number of pictures of various airplane setting measurement methods and various Flight design ideas:

https://drive.google.com/drive/folders/ ... share_link

With the flaring prop shown, slightly higher rubber density (and slightly shorter motors) are typical as compared to motors for the Ikara 24 cm symmetrical prop. Also note that the propeller hook is not stock. The diamond shaped hook holds the black rubber o-rings better than the stock Ikara hook.

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Re: Flight B/C

Post by bjt4888 »

Here is a folder with a number of pictures of various airplane setting measurement methods and various Flight design ideas:

https://drive.google.com/drive/folders/ ... share_link

With the flaring prop shown, slightly higher rubber density (and slightly shorter motors) are typical as compared to motors for the Ikara 24 cm symmetrical prop. Also note that the propeller hook is not stock. The diamond shaped hook holds the black rubber o-rings better than the stock Ikara hook.

Brian T
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Re: Flight B/C

Post by coachchuckaahs »

danxmemes wrote: February 1st, 2023, 3:23 pm thank you! I do not have a good flight log, but I will be starting one asap. I do agree that it flies very flat, so I will be changing that. Again, thank you for all the help!
I cannot emphasize enough how important a good log is starting with your first flights. Without a good log, you have no data to review to determine what changes, and to what extent, helped or hurt your performance. The flight log is not just an exercise that must be met to get full points. The flight log is instrumental in you getting the highest score possible for your device.

A well-organized log, with a two-person team, will not seriously degrade your flight time in the gym. As one person winds, the other can be filling in the log for the upcoming flight. Additional observations are added during the flight and immediately after. I would contend that NOT doing a log will result in wasted flights that do not add to the knowledge, and thus less efficient gym time utilization.

While the primary benefit of the log is for you, as a team, to study your variable adjustments and impact on score, a second benefit comes in when you are asking outsiders for help. While your memory is not as good as a log, we have no memory of the flights you are asking us to evaluate. If you look at various queries for help on this and other forums, you will find that quite often the experts ask you to divulge details from your log in order to fully understand what is going on.

Start those log sheets!

Coach Chuck
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Nationals Results:
2016 C WS 8th place
2018 B WS 2nd place
2018 C Heli Champion
2019 B ELG 3rd place
2019 C WS Champion
AMA Results: 3 AAHS members qualify for US Jr Team in F1D, 4 new youth senior records
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Re: Flight B/C

Post by randomdogonapc »

Thanks a lot, I didn’t know about the wide bladed Ikaras. Will make sure to get my hands on one.
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