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| General RC Aircraft Discussion Discuss anything RC related |
Topic Review (Newest First)
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| 04-19-2013 12:06 PM | ||
| Trumpetman |
Re: whats the main causes for Maiden crash's JohnA: I hope you don't mind but I will be copying your list and adding it to our club e-mail newsletter. Excellent list of do's and don'ts for those first few flights this spring! |
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| 04-19-2013 08:37 AM | ||
| Dave Holmes |
Re: whats the main causes for Maiden crash's JohnA, I just copied your list to a file on my hard drive, I expect I will use it to coach newbies, and to keep my own mind fresh. It covers everything I ever thought of and more. Thank you. |
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| 04-19-2013 02:09 AM | ||
| rbwater |
Re: whats the main causes for Maiden crash's Nerves are a big part of the reason for maiden crashes. Even though I'm a fairly experienced pilot, I'm not too proud to ask for help with a maiden. One method I use to increase the chances of surviving a maiden of a new plane which is a step up from my previous one is to buddy box with a friend of mine who is a very good pilot. The most recent example was a move up from a 52" plane to an 89" plane. If I'm feeling nervous, my friend will take her up & give me control for most of the flight & land for me. The second time I will likely take off & land but I still have a back up if it looks like I'm going to get it wrong. Even now, the first time I fly the "big Yak" this spring I'm going to ask him to buddy box with me - he may not touch the sticks at all but if something goes wrong, two heads/sets of hands are better than one! RB |
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| 04-19-2013 12:29 AM | ||
| bristolbullit |
Re: whats the main causes for Maiden crash's well that sums it up John . I will say C of G and dead stick have got me . Never lost a plane but caused a few more grey hairs . I did have a rear stab blow apart in flight on a 50cc yak (poor glue on tube it just fell apart ) . Put your plane together in solitude dont chat while doing this . Then if nervous get someone to go over it with you then start the video camera |
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| 04-18-2013 11:08 PM | ||
| JohnA |
Re: whats the main causes for Maiden crash's Here is a first flight check list I wrote up for my club. First Flight Check List First flights shall be relatively short in duration and be devoted to checking out the "trim" of the aircraft. This should include slow flight and stall characteristics to assist the pilot with first landings. Control limits, roll rates, climb rates and glide rates should also be included. Conduct the first flight on during optimal conditions. The conditions may be ok for that type of airplane, but are they acceptable if the plane has a serious condition? Your first flight (or first week) of the new season should not be a maiden. Take out your old faithful for the first few flights. Items to check at home Balance and Alignment ·Is the longitudinal center of gravity (fore and aft) within the range shown on the plans when the fuel tank is empty? ·Is the model balanced laterally (side to side)? ·Are there any twists in the wing or tail? ·Locktite all nuts and bolts. This is especially important in gas models. ·Is the propeller nut and spinner tight? ·Make sure the prop does not touch the spinner at the cut-outs. ·Has the propeller been balanced and checked for damage? ·Propellers must have the edges rounded to prevent cutting your hand. ·Is the fuel tank installed correctly? (i.e., carburetor at the same height as fuel tank, clunk in proper position and moving freely, fuel lines in good condition and connected to the engine correctly, no kinks in fuel lines) ·Test for proper and bind free low idle and full throttle. ·If the gas engine has been sitting for the winter, clean the carb screen and unstick the flapper valves. ·Mix up fresh fuel. Never use last year’s gasoline. ·In the case of ignition engine powered aircraft, they shall be capable of being shut down from the transmitter by an alternate means to the throttle control (for example a separate servo operated kill switch.). An engine kill switch on the aircraft that can be operated by a person holding the plane is also required. Verify that both work. Radio Equipment and Control Linkages ·Is the receiver's 72 mhz antenna fully extended without strain and in good condition? 2.4ghz antennas are properly orientated? Avoid close proximity to metal and wires. ·Are servo arms firmly attached with screw in place? Locktite metal servos. ·Are the control throws in the correct direction with proper amount of deflection (as per plan)? Including the nose wheel. Do not just wiggle the sticks. ·Ensure that rudder and elevator arms do not interfere with each other through their full range of movement. ·Ensure that wires inside the fuse can not get caught in servo arms. ·Set-up dual rates. Expo should be between zero and 30. ·Ensure that batteries are secure and can resist flight Gs. (up or down) ·Trim steps should be set to course so you can make large trim changes quickly. ·Test servo current draw to detect a bad servo or binding pushrod. ·Control surfaces must return to center after deflection. ·Test voltage at end of long wire runs to detect excessive voltage drop. ·Verify the failsafe works and throttle goes to idle in the event of signal interruption by turning off the transmitter and observing the results. Separate failsafe devices can be added if you receiver does not have this feature. ·Servo and control horn arms should be 90 degrees to pushrod when centered. ·Battery connectors and servo extensions held together with clips or ties. ·Batteries (especially new and old ones) are tested and cycled. ·A dual battery system for redundancy with separate switches for each battery is suggested for larger models. ·Are all control surfaces securely attached? (i.e., hinges glued, pinned). Pull on each one to test. ·Hinge gaps should be sealed or less than 1/16”. ·Are all the clevises closed? (keepers or fuel tubing should be fitted to ensure they stay closed) Are the rods threaded into the ends enough? ·Turn on the radio and check for slop in the control linkages by grabbing the outboard end of the control surface and gently moving it up and down . It should not move more than a degree or so. Too much free movement can result in flutter. ·Check for control springiness. Hold or clamp the control surface so that it can not move. Apply a load to surfaces by moving the transmitter stick slightly and check for any flexing of control cables/rods. Watch the linkage for twisting of the horn or servo arm or flexing of the pushrod. Ball linkages are a prime cause of twisting arms. ·Check for binding and erratic servo performance. Slowly move servos through their complete range not just jamming the sticks back and forth. Be sure they operate smoothly throughout the entire control range. At the field before the first flight Control Surfaces and Linkages ·Are all the clevises closed? (keepers or fuel tubing should be fitted to ensure they stay closed) Engine / Motor Security and Operation ·Is the propeller nut and/or spinner tight? ·Test for proper and bind free low idle and full throttle. Does the throttle trim tab shut down the engine? ·Fill tank and visually verify that it is full. Drain the tank using the tube that goes to the carb and visually verify that it is empty. If you use a drain line that goes to the bottom of the front of the tank, hold the nose high as you empty with the engine pickup line to test that it is not mixed up with the drain line. ·Check for bubbles in the fuel line while the engine is running. ·Verify that both the servo operated kill switch and the kill switch on the outside of the aircraft work. Radio Equipment ·Are the batteries charged and in good condition (check under load with a volt meter)? ·Dual rates set up for first flight ·Turn on transmitter and check the correct model is selected (if applicable) and then turn on the receiver. ·Ask someone to help and walk away from the model until signs of loss of control are apparent. ·If electric powered ensure that the range is not worse with the motor running. ·Gas planes - Run a similar check with the engine operating at power levels from idle to maximum power. If there is range degradation with an operating engine there is an issue with ignition noise and/or a vibration induced problem. ANY reduction in range means a loss in signal/noise ratio and a chance of control loss in flight. ·Test reception with a data logger ·Do not taxis airplane around until it is completely ready to fly. Taxis tests quickly and accidently become first flights After the first flight ·Check for loose bolts, muffler looseness. ·Check prop nut tightness. ·Check battery voltage to determine of the battery has been depleted more than expected. ·Check fuel level to determine if actual consumption meets expectation. ·Adjust the dual rates and expo. Adjust the control linkages for proper throw rather than reducing servo movement in the radio. ·Adjust the CG location only a small amount before retesting. |
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| 04-18-2013 10:26 PM | ||
| zdsh13 |
Re: whats the main causes for Maiden crash's Don't force yourself to get a maiden completed, all the work invested in getting the airframe ready could be lost in just a few seconds. Preflight is essential, control throws, CG, batteries, engine operation all need to be validated before even considering to perform the maiden. I prefer to avoid maiden flights at fun flys or in front of a spectator crowd, only my closer flying buddies. Preflight of the model with experienced modellers will avoid the no brainier mistakes which sometimes catch us all. I will not maiden any airplane unless the conditions are right... Ie: weather, wind etc... It nots worth it, you have nothing to prove, only $$$ to lose... If the plane is potentially above your flying skill get a skilled pilot to perform the maiden, and the initial trimming of the plane... There no shame in this. Once your satisfied everything is good to go, perform a final check of the control surfaces... Don't just wiggle them... Think about what you doing.. Is right aileron actually dropping the left aileron and raising the right.... I've seen experienced pilots lose an airplane on reversed ailerons, their wiggle test just proved that the control surface moved.... Period.. Your goal for the first flight should be to trim the aircraft and once stabilized get a feel for the flying characteristics, don't overdue it.... Just basic flying. Ensure your flying is at least a few mistakes high and prior to landing check the slow speed characteristics for how the plane reacts to a stall... Does it drop a wing on stall or just the nose etc... This will help you identify the condition before it happens when you are low and slow on landing approach After your first flight check all control surface linkages, mounting bolts and airframe structure for any problems. Hope it helps.... If you have any doubts on something don't feel pressured to fly.... That's usually when things go wrong. |
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| 04-18-2013 10:09 PM | ||
| Pauld |
Re: whats the main causes for Maiden crash's Preparation is king. Rushing to the field with a plane u finished off the night before at 1:30 something is just increasing your chances for a disaster. I like getting others to check things out. And yes, it helps to go to the field when there isn't a ton of "helpers" pointing at your plane - "youshood......" My big pet peeve is the "I put the cg forward of the recommended location to play it safe" -guys, take the time and get the CG right the first time. If you're not sure, that's what these forums are for -do some research. Nose heavy airplanes land like s$$t... PaulD |
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| 04-18-2013 09:38 PM | ||
| DarthAnal |
Re: whats the main causes for Maiden crash's One item that I haven't seen is to take your time and ease into pushing the corners of the flight envelope. Even the Big Guys do this. First flight (even the one for the Avro Arrow) is essentially one takeoff, one landing, basic flight manuvers but nothing that puts stresses on the airframe. All loops and stall tests are basic and nothing fancy. One short easy flight, then check everything for possible loose items, fuel up and go back up again. Repeat as required to get a good feel for the airplane and to recognize what's happening. Then shift into aerobatics when you're sure that nothing will fall off. |
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| 04-18-2013 05:22 PM | ||
| Cross Check |
Re: whats the main causes for Maiden crash's Hi All, Enjoying this thread!  I figure it is the Test Pilots job... to make sure the plane is ready to fly. Don't agree? You are 'Myth'taken....  Take care, Have fun, Dave'crosscheck Fallowfield Maac 6437 Unabashed Combat Team |
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| 04-18-2013 03:04 PM | ||
| Dave Holmes |
Re: whats the main causes for Maiden crash's Quote:
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