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Lee's blog
Posted by Lee | Feb 15, 2008 @ 08:05 PM | 22,531 Views
Welcome to my blog. All of the posts in this blog cover different topics for new flyers.

All of this information is updated at our website:
http://www.crashtesthobby.com/

This is a link to our club threads on RC Groups. If you want to fly with us and want to know when and where we will be flying look here.
http://www.rcgroups.com/utah-flyers-organization-241

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These are links to some of my build threads.
48" Albatross and 36" Pelican Trainers http://www.rcgroups.com/forums/showthread.php?t=1538751
66-78" Hercules Gentle Giant FPV flying wing http://www.rcgroups.com/forums/showthread.php?t=1473169
26" Scythe flying mini/micro wing http://www.rcgroups.com/forums/showt...php?p=14511077
58" Grim Reaper http://www.rcgroups.com/forums/showthread.php?t=1192820
58" Titan flying wing http://www.rcgroups.com/forums/showthread.php?t=1121604
36" Roswell Delta http://www.rcgroups.com/forums/showthread.php?t=1103999
34" Assassin http://www.rcgroups.com/forums/showthread.php?t=1052384
24" RET Snowball http://www.rcgroups.com/forums/showthread.php?t=930241
Capricorn http://www.rcgroups.com/forums/showthread.php?t=898958
The Q-Planes RET http://www.rcgroups.com/forums/showthread.php?t=931080
EPP Peregrine http://www.rcgroups.com/forums/showthread.php?t=950519
Goblin http://www.rcgroups.com/forums/showt...21#post4685892

These are links to airfoil data bases.
http://www.ae.uiuc.edu/m-selig/ads/coord_database.html
http://www.aerodesign.de/english/pro..._s.htm#sipkill
http://www.worldofkrauss.com/
http://www.mh-aerotools.de/airfoils/
http://www.b2streamlines.com/PWairfoils.html
http://www.twitt.org/

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Posted by Lee | Apr 01, 2007 @ 11:16 AM | 23,610 Views
Getting Started in Radio Control #1

Getting Started in RC

Welcome to my blog. All of the posts in this blog cover different topics for new flyers. I have tried to add links to take you to more detailed information and videos to inspire you. I have been updating this information base since May 6, 2006.

As one of the local RC club trainers I get asked the same questions by most every new flyer. I started writing them down and have been putting the answers here.

I spent hundreds of dollars I wouldn't have spent if I had received better advice when I started building and flying radio control airplanes. I wrecked 7 planes learning to fly. I got frustrated with planes that were too fragile and didn't protect my radio. I had to send my radio in several times for repair of damage from accidents I had. Hopefully I can help you avoid the same expenses.

My sons each learned to fly on their first plane which was an EPP flying wing. In fact all of their trainers are still flying. Why did we choose this design?

I kept dreaming of a plane that was bulletproof but didn't know where to look. I finally saw a video that changed the way I teach new fliers to fly. The video was of a RC flier intentionally hitting a fence with an EPP flying wing over and over and over and the plane kept on flying. If you don't know anything about EPP foam it is so tough it is used in car bumpers. It doesn't crush so even when it is smashed or tears it maintains it's...Continue Reading
Posted by Lee | Dec 18, 2006 @ 03:02 PM | 24,017 Views
Getting started in Radio Control #2

It's hard to stay excited if you crash every time you fly, especially if you have to go home and fix your plane. This is the main reason I am a fan of EPP deltas and EPP flying wings as trainers. They they are simple and durable. Deltas and flying wings can be built and repaired in a fraction of the time of many other trainers. I carry a hot glue gun to the field and do some simple repairs at the field.

I had a gas/fuel flier who built balsa planes with nose mounted motors tell me that he didn't think there was that much difference in the durability of the wings verses what he was flying, so I flew some vertical aerobatics with my EPP flying wing and finished with an intentional dive into a brick wall at half throttle and turned to him and said "Your turn!" Of course he didn't do it and he knew that his plane couldn't hit a wall and survive. I picked my plane up and flew it again without any adjustment or repair.

I avoid the high maintenance planes. I used to build fiberglass planes that took 100s of hours to build and they were fun for a while but I burned out because of how much time it was taking to keep them flying. I hardly flew for most of 3 years because of burnout and frustration. I got my enthusiasm back when I went back to simpler planes.

No one else really cared that I had these super planes. The truth is everyone will be more concerned about their own projects than about yours. Other fliers like to see what...Continue Reading
Posted by Lee | Dec 07, 2006 @ 01:12 AM | 24,781 Views
Which plane should you buy as your first plane ??? If I were teaching one of my sons to fly today, I would have his first trainer either be an EPP delta like the EPP Roswell, or an EPP flying wing like the EPP Assassin. I would buddy cord with him to help him fly without having an accident and I would have him spend time on one of the simulators until he feels comfortable with the controls.

As you look at the videos remember that some of theses simple planes are being flown by advanced flyers. The Capricorn and the UFO Roswell Delta for example are easy to fly slow in flat and level flight. In both of these videos I'm the pilot and I tend like to do aerobatics even when I'm flying a trainer.

I like flying wings because there they are so simple and the motor is in the back. My new Assassin is designed for beginners. Notice the launch and catch in the video.

Assassin #1 RC Combat Wing (2 min 38 sec)




...Continue Reading
Posted by Lee | Nov 30, 2006 @ 12:22 PM | 24,298 Views
Gas vs Electric

I still own both gas/glow planes and electric planes and I haven't flown the gas planes for years.

Electric planes probably cost more to fly because of the price of lithium batteries, brushless ESCs and the cost of electric motors. With the Chinese starting to produce parts the price is dropping drastically in electrics from what it was 5 years ago. The price is more equal now than it was in the past.

There are several reasons to fly electrics:

#1 The shrinking open spaces in our community is taking away our flying sites. I can fly my electric plane indoors or in front of my house or in a small park and people hardly know I am there. I have times I can't hear my electric plane over the regular city sounds. The engine noise and fuel on the grass make the gas/glow flyers not welcome in very many places anymore.

#2 My wife didn't like the gas planes because of the smell in the house and the spots on the carpet from fuel dripping as I would carry the planes in. I didn't like greasy planes and the constant clean up.

#3 I really really didn't like trying to start the planes and get them to idle in the cold with alcohol based fuel on cold hands. It almost ruins winter flying for me.

#4 I didn't like dead stick landings which rarely happens with electrics.

#5 The planes are smaller and safer. I don't have an electric plane that weighs over 2 pounds. Most are under 1 pound. You just aren't going to do much damage with something that...Continue Reading
Posted by Lee | Nov 30, 2006 @ 12:11 PM | 24,047 Views
Batteries, ESCs, Chargers and Bunkers

I didn't want to have to buy all of the different sizes of batteries and ESCs for my fleet of planes so I decided on a specific battery and ESC combination that could be used in a wide variety of designs and now I only design and buy planes that will work with this set up. This decision has saved me money because I don't have to buy batteries and ESCs of different sizes to match different planes.

Lithium batteries are made with different sized cells just like the AAA, AA, C, D batteries we use. The differences are that the Lipos have 3.7 volts a cell rather than 1.5 volts a cell and they have the ability for a much higher discharge rate for the same weight. Remember weight is everything.

Lipos also can be wired is series or parallel but the most common configurations are 2 cell and 3 cells in series resulting in 7.4 volts and 11.1 volts respectively. I use exclusively the 3 cells and base all of my motors speed controls and props on this set up.

Lipos have a "C" rating which tells us how many amps they can produce safely. The C rating can be used to to calculate a continuous amperage output limit. The C rating times the lipo battery's mA rating tells you how many amps you should be able to get out of the battery. For example a 1500 mA 20 C battery could produce 30 amps of power. A 1500 mA 40 C battery could produce 60 amps of power.

Some less expensive batteries are heavier or have a lower amp rating so...Continue Reading
Posted by Lee | Nov 26, 2006 @ 09:24 AM | 24,551 Views
Radio, receiver, servos minimum requirement

In the last few years new technology has changed. We used to have to watch and check frequencies but the new radios don't interfere with each other. I got the new Spektrum DX6i that is one of the new 2.4 gig radios and I think it is the best radio I have ever owned. I also think that it is an outstanding deal for a radio with this many features.

The Spektrum radios do not have an assigned frequency but code themselves with the receiver when you turn them on. So far in the group they have operated well even with 50+ flyers in combat at the same time. The Spektrum comes with both large and small recievers that have been some of the most reliable I have used.

Be careful with some of the older radios. I know there are older radios out there you want to dig out and fly with. Many of these older radios get interference form the electric motors. I learned this on the hard way with my "gold sticker certified" Futaba AM Attack 4 radios. If you are trying an older radio cutting the throttle will usually stop the interference problem if it is from the electric motor and speed control. It is advised you stay with FM newer model radios or the new Spektrum line of radios.

Futaba and JR radios are also common. Make sure receivers, servos, batteries are readily available in your local hobby shop for what ever brand you buy. You need to plan so that all of your accessories are compatible with the next radio you want to buy....Continue Reading
Posted by Lee | Nov 05, 2006 @ 02:14 PM | 24,391 Views
Basic battery, ESC and motor set up.

Each motor ESC and battery have a maximum amp rating. The simple rule is that the one with the lowest rating is the limit that the entire system can handle. It's the weakest link rule.

HobbyCity recommends that every flyer gets a wattmeter

Personal note from the hobbycity director.
I believe a good amp meter is a must have for any EP flight hobbiest.
If everyone of our customers used one of these items, the number of burnt/returned speed controllers would be a great deal less.
Knowing how many amps your motor is drawing with a given propeller is essential in determining flight times and battery/esc sizing.
I cannot stress enough the importance of this item.
Anthony


A realistic case study would be:

I have a brushless motor with a 14 amp rating I want to use with a 25 amp ESC and a 3 cell 1320 lithium polymer battery that has a 17 amp continuous rating. I see on the battery that it has a second rating of 27 amp peak rating. The peak rating is for only short bursts of power of less than 5 seconds. I'm planning on flying on hot summer days Which won't allow the batteries to cool as well and I don't want damage the batteries so I only want to use 13-15 amps most of the time.

YOU ADJUST THE AMP DRAW FOR THE ENTIRE SYSTEM BY THE PROP YOU PUT ON THE MOTOR.

This is a very usable set up as long as I put the right prop on it. In this example I don't want to have more than a 14 amp draw at WOT (wide open throttle) because the lowest...Continue Reading
Posted by Lee | May 06, 2006 @ 05:19 PM | 25,844 Views
THERE ARE NOW 3 LIPO FIRE VIDEOS AT www.utahflyers.org.

I'm a "Mythbuster" fan and thought it would be a good project to separate myth from truth about the lipos. I have heard alot of different things, most of which are based on some truth.

The question of "Can a lipo catch fire and start a house fire". Has already been answered by two local flyers. Now the obvious way to prevent lipo fires is by being careful and that works most of the time. It's that one out of 10,000 charging times that comes into question. That once you set the charger wrong or the battery is damaged. So when that happens will your house burn down if the lipo catches fire?

To test this out I needed some lipos that could be destroyed for the sake of science (and fun) and to know what bunkers people were using so I could test a few of the ideas. Our local club tends to be pleasantly paranoid about the dangers and have been quite willing to offer suggestions and donate older batteries rather than throwing them away.

The lipos have to burn to see how a bunker works so my first task was to learn how to get them to burn on command so I could catch it on film. Now for all of you who are concerned that I had the charger set wrong. I had the charger set right......I wanted the batteries to burn.....That is the idea.

I have heard about people charging lipos in bath tubs, showers, buckets, fish tanks, cinderblocks, brinks boxes, amo cans, metal garbage cans, and in planes. Did...Continue Reading