A Model that flies gathers no Dust!

[Mitch]

Day 2 report: I HAD A GREAT TIME!

0730: First in the morning I was "mechanic" for my new friend Herb, flying an endurance plane. While winding his motor the rubber broke. Even with the blast tube it nearly destroyed the fuselage. I thought he was done. Undaunted he took that out. Put in another, wound to less than full power with no blast tube. Launched his plane with seconds to go. I timed and tracked (with binoculars). He WON the event!!!!
3 minutes and 10 seconds. A lesson in never give up!

After that, the air was still calm, test flew my PT and flew and trimmed out the Mustang! The 'stang was flying nice and I think she is ready.

about 10:00 a friend of mine showed up with another buddy. So I come all this way and I have my own "support team"!

11:00 Low wing mass launch: The PT is wound to nearly full power and at the launch pulls hard to the left (a lot of torque) and she wings over and dives in. She is so light there is NO damage, but I am out for the next round.

13:00 WW2 Mass launch: I made a new motor for Miss Scarlet. More powerful than I have ever used....

To Be Continued, I have to go to diner... Mitch

UPATE: I'm back...

Okay so I am hopeful that the Mustang will do well. She was flying very nice in the morning for her trim flights. My friend is my mechanic and holding my plane. So the order is given to "start winding". We have 2 minutes. I have calculated my motor can safely take 1740 winds. My plan is 1200 for the first round. (1400 second, 1600 third). I stretch out several feet and start winding... I slowly walk into the plane as I reach 1200. I am using a crocket hook, so I have to take off my winder and hook the prop. I find it is not easy to hold the rubber, as there is a lot of power in the rubber. I manage to safely get the prop on and now I notice the front plate is slipping around... I hope the 4 magnets will hold the front plate in place...

The line is spread out to the right and left of me, and the CD (contest director) Says..."3...2...1....Launch" I let go of the prop and smoothly toss the plane straight ahead...

Instead of climbing away... the plane is flying straight ahead... with all the power in the motor the plane is shaking violently... Just when I think she should be pulling up rolls to the right and down and plows into the ground. I KNOW there is a lot of power still in the rubber so I quickly go after model and pick her up so she doesn't beat herself to death. She is already tumbling on the ground.

So... My flight was 3 seconds. She was doing 15-20 seconds under half power in trim flights. What went wrong?

Damage Report: Tail is broken, but not much else, Easy fix, but I intend to replace tail with a stronger/heavier one anyway. She will be repaired when I get home.
Crash Analysis:
1. I believe the power in the motor along with the shaking of the model caused the front nose bloke to rotate around, causing the thrust direction to change.
2. The violent shaking can be 2 things. Unbalanced propeller, or unbalanced knots in motor.
Corrective Action:
1. Front block NEEDS to be secured with HARDWARE. Magnets are NOT sufficient for that purpose.
2. Make sure prop is balanced. Use a bit less rubber, until I get everything else working in harmony.

GOOD POINTS:
1. Break Away wing worked as it was supposed to.
2. Miss Scarlet was a beauty in the pit area getting serviced, and in the air when she was flying well.
3. I had a GREAT TIME with Old and New friends and was in a competition with the countries best fliers.

The wind was getting stronger and I decided to call it a day. I will repair Miss Scarlet when I get home and fly her at my local field with conservative power.

Good Night...and Good Flying to all. Mitch

PS I will post some pictures when I get home!

[Steve Blanchard]

Mitch,

What went wrong was that you were trimming at half power and a different motor size. You have to trim it to full power before you enter the competition for just that reason. You change the power and you change the way it flies. Also you mentioned the noseblock was slipping around. Not a good sign at all. The adjustments that you built in when trimming are now anyone's guess. These are all lessons to be learned when doing this. The guys I fly with keep journals with each plane in it. They indicate the rubber size and length as well as the number of winds (because calculations are not always safe). There is a lot to it but when it goes right it is magical.

Steve

[duk774]

Hey, Mitch! I posted a question on"Building my Fokker DR-1 that you answered above. Sorry your flights didn't go well but there's always next year
Also, congrats to your new friend who won his contest.
The good part is you had fun and learned. Isn't that what life's about?

Bill

[WIDDOG]

Glad you had a great time. Thanks for posting. It was very interesting reading. Everything was perfect with the P 51 I assume the propeller was balanced? Anyway I am kind of curious what you use for Lube. I started with Armor All tried different ones and now am back to the Armor All.

[Mitch]

Thanks to all for your feedback. I know I took shortcuts and this model was rushed into service. From box to competition in less than two weeks! I was also working a job and assisting my daughter on my day off and went to a motorcycle show. I built a new airfoil wing and three different tails, and was also working on other models at the same time.

I am now resting at my FAC friends house in Casper, WY. As Steve says he, just like my FACer in Las Vegas, keeps a journal on all his builds, motors, flights. It is like a Science Project and I would give them both an A+. My friend Bob (NV) hangs his models from above in his work space (3rd stall of the garage). My friend Tom (WY) has a chain all around the top of the wall and hangs his models on that in his work space.

I need to:
1. Keep track of what I am doing
2. Have a dedicated work space
3. FINISH some incomplete projects

As for my nose on the P-51... It was only held on and held in place with 4 little magnets. I adjusted the thrust line by shimming the nose button. It all worked under half power and I had nice trim flights. I broke a prop and replaced with new (unbalanced) prop. DON'T TAKE SHORTCUTS!

When I was at the start line for WW2 mass launch, I knew I was in trouble when I had a VERY difficult time holding the motor to hook on the prop. I NEVER had this much power at my disposal. When I set the Nose plate against B-0, I could feel the power of the rubber was way more than the strength of the magnets! I thought... Oh well... Here we go... 1.2.3...launch. I was hoping the power would transfer to the prop, but I never saw the P-51 shake so much... She was zooming straight ahead. I had to yell to the CD "INCOMING, WATCH OUT!" The CD was directly in front of me with 3 planes to my left and 3 to my right, all soaring skyward. The CD stepped aside and we all got a laugh afterward about my "strafing run" on the CD.

Mitch... ALWAYS having FUN!

PS The lube I use now is what Tom gave me, Dow Corning lubricant 33. It comes in a green tube. You have to wash your hands off with alcohol... Rubbing Alcohol, not the other kind... I would call that Alcohol Abuse!

[Wildpig]

Exciting and fun!

As for the P-51 shaking, what kind of propeller hook are you using? If it's the standard round, shepherd's hook thing, this can cause problems. The rubber motor will climb up the hook, causing terrible vibration problems.
I use a "reverse S" or "Z" hook. Smooth power.

[Steve Blanchard]

Well Mitch I have done all of the same. That's why it was so easy for me point them out! It is sometimes irresistible to just take the latest flight and tweak at the last minute. I totally agree with Wildpig about the reverse S hook. Smooth as silk!

[goose]

As for my nose on the P-51... It was only held on and held in place with 4 little magnets. I adjusted the thrust line by shimming the nose button. It all worked under half power and I had nice trim flights. I broke a prop and replaced with new (unbalanced) prop. DON'T TAKE SHORTCUTS!

Mitch, Why don't you replace two of those magnets with dowels that are glued into the nose block, with corresponding holes in the plane? That way the dowels will take the torque, and all the magnets have to do is keep the nose from falling off when the rubber unwinds. Just a thought.

Sorry I missed you in Denver, I have enjoyed following your builds and was hoping to see you, but I was out of town this past weekend and was not able to make it out to the field to watch.

Mike

[Mitch]

I have a couple of issues with the nose block. I will leave the magnets there as they are glued in. I will add 2 small nails (for alignment, @ 12 and 6 o'clock) and 3 small screws (for thrust direction, at 11, 1, and 3 o'clock)

I will make changes and improvements on Miss Scarlet... but I think I will also make her replacement. I will try to cover all of the issues I have with Miss Scarlet and make those corrections into the next build. I think Miss Scarlet still has a lot of potential.

My first P-51, Miss B. Haven was built as per Guillow plans, and although she flies, she did not do well in competition. My second build of Miss Scarlet, I think I over did some of the build and need to find a balance. My next build will be "Goldie Locks" I have to find that spot in the middle that's just right!

Sorry I missed you also, but I had a friend show up, and he brought another friend. So for the day of my "Big Show" I not only had my own mechanic, I had a photographer. Not bad for the new kid from out of town with his Guillow models! Mitch

[davidchoate]

nice planes. i agree with that Guillows produces a better SCALE model. on my rubber motor modele i have to add a tremendous amount of weight to get balance. i know its cause the full scale had a huge engine, but i get a sick feeling every 1/1oz. wgt, i stick on. i mean , i was very careful to keep it light, and here i am now adding 20g of lead to the cowl! did i do something wrong, or hane you had a similar experience? thanks.

[Mitch]

Hello and Welcome,

That seems like a lot of weight. But I just weighed the plastic cowling from "Miss B. Haven" and cowl/screws/clay weigh 21 grams. That plane was built last year, built just as per Guillow plans and weighs in at 100 grams. My newest plane "Miss Scarlet" was built with the purpose to fly in FAC rubber competition. She weighs 75 grams and was built without any nose weight. She did not need any. Check out the build post "2 Mustangs in 2 Weeks"

I have found that a plane built as per Guillow plans with ALL Guillow parts, with have nice moderate flights. To get the most potential out of these planes I believe you MUST make some modifications. I am still learning. Here is basically what I did:

1: Make entire plane as light as possible.
2. Use lighter balsa wood
3. Move rear peg fwd / Keeping center of rubber motor over center of CG.
4. Keep everything aft of peg as light as possible. Every gram you save in tail is 2-3 grams of ballast.
5. I did not use cowling and made front end out of balsa. You need to modify the front for thrust adjustment and ease of access.
6. Use a larger Prop. I am now using 9-1/2 inch Peck Prop.
7. Use more rubber. My last flight was with 3 strands with a length of 2 X hook to peg length.

I have flown the P-51 with Guillow rubber and prop. If you go with larger props you need to increase the loops of rubber to have enough torque to turn that big prop. I am still experimenting, and think I will try 4 loops for MORE torque.

I believe "Miss Scarlet" has potential to get into the winners circle, but I am already planning a newer version of the Guillow's P-51.

Hope this helps. Mitch

[WIDDOG]

The nose cowling has to be modified as well.