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Speed,Combat,Scale,Racing => Scale Models => Topic started by: John Rist on August 09, 2013, 02:01:20 PM
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Well my DO-335 is out of paint. Next a ton of work with the ink pin and add decals. It will be close for FCM this year.
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Looks awesome so far. Dare I ask about weight?
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Looks awesome so far. Dare I ask about weight?
It's heavy but with two TDs churning it should go!
LL~
Just weigh the DO-335. It looks like 23-24 oz. However it has a 24" wing span and approximately 120 sq in so it should fly OK.
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Decals generated and applied. Ready for clear coat. Next step is install two Cox 049, prop shaft with rear bearing, and fuel tanks. Question? Is it legal to remove fuel tanks for scale judging?
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Don't know about the 1/2a rules in various places, but in all the other events it would be illegal to remove the tanks. The rules are very explicit about what can be changed.
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If you were to bring it to our 7th annual 1cc event here in Tucson, Oct. 12-13 (and I wish you would....it's a beauty!) the tanks should be left in place.
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That's what I thought - I will just paint them to match.
y1
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If you were to bring it to our 7th annual 1cc event here in Tucson, Oct. 12-13 (and I wish you would....it's a beauty!) the tanks should be left in place.
Wish I could but it is 1616 miles from my house. That's 6 days travel time by car Total trip time is 10 days. Maybe some day but not this year.
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Well my DO-335 is ready for engine test running. The big concern is will the rear motor drive the prop shaft. Will post results.
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More ready for test run.
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Thats a work of art. I sure hope it flies as good as it looks
. H^^
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That's really cool, nice job. Don't be surprised if a .40 sized version pops up somewhere at some point. VD~
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Well I just finished test running the two engines. They ran really good. I am not sure what you would call them. They are a mix of parts. The rear started out as a Medallion .049. It now has an after-market aluminum housing that replaced the red plastic housing. It is also sporting a brand new product engine piston and jug. The front started out as a TD .051. It has an after-market aluminum housing that replaced the red housing. It also is sporting an after-market venture that has a micro set needle. And last but not least it has a brand new product engine piston and jug. They seem to be happy on 15% fuel.
My first test run lasted for about 2 minutes should be long enough for 10 laps. On the test run the front quit first. I hope to adjust everything so that the rear quits first. However with the inline engines it doesn't matter. It should fly on either engine well. If all goes well I hope to test fly tomorrow or Saturday.
#^
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That little bugger looks great.I'll be at the FCM and can't wait to see it fly.
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If the plane flies as well as it looks in the pictures and your documentation is up to snuff, you have winner.
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Well as the old saying goes we want 70 deg temp, no wind, and no rain for a test flight. Today was such a day except for the no rain. Well it wasn't exactly raining but it was misting. A mega thanks to Rollin Keszler for coming out in this slop to be my pit crew and take picture of the first flight of my DO-335. #^ H^^
Now for the flight report. She flies great! The take off was a little rough. I tried to lift too soon but it made it into the air. It is a bit of a lead sled and will need 3/4 of a lap to come up to flying speed. In other words Requires a true scale rollout on take off. Once airborne it was stable in level flight with good line pule. At 30 laps the front engine quit. She made a smooth landing on one engine (rear). Taxied for about 2-3 laps and the rear engine quit. All in all a really good flyer.
Photos courtesy of Rollin Keszler:
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Out of curiosity. Are you saying with only one engine it would not have flow for a few laps ??
Reason I ask this is i had a sterling p-38 . the 1/2a one and the one time i flew it the engines were very rich and it rolled almost 3 laps before they leaned out and it flew ....though I think that was the only time I flew that model.
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Out of curiosity. Are you saying with only one engine it would not have flow for a few laps ??
Reason I ask this is i had a sterling p-38 . the 1/2a one and the one time i flew it the engines were very rich and it rolled almost 3 laps before they leaned out and it flew ....though I think that was the only time I flew that model.
The front engine is stronger than the rear. The rear is turning that big U-joint and prop shaft. It might fly on the front only but with rear only it would be a struggle. Anyway landing and taxi on one engine was cool!
#^
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Great John! I think I might be able to make the FCM on Saturday after all, so bring plenty of fuel and conversation with you!!!
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That is great news about the plane. Now go show them at the FCM contest.
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To soon to tell but the weather looks good for the FCM @ the AMA August 24, 25 2013. SO the plan is for me and my wife Peggy to make the trip. I will bring 3 airplanes. My electric 576 Ringmaster, my Extra 300S, and my DO-335. Hope to get in some fun flying with the Ringmaster on Friday. I need to learn the novice pattern. Right now I have attempted everything but the overhead 8.
What time does the scale contest begin on Saturday?
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John,
Just curious, what length/diameter lines are you using?
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John,
Just curious, what length/diameter lines are you using?
Dornier Do-335
Scale = 1/22.5
Model wing span = 24"
Model Power: Two Cox TD .049
Model weight: 23.5 oz (1.46 lb)
Line set: .010" x 2 x 38' SS Braided
Pull Test: 1.46 lb x 10 = 14.6 lb ( 14 lb, 10 oz.)
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To soon to tell but the weather looks good for the FCM @ the AMA August 24, 25 2013. SO the plan is for me and my wife Peggy to make the trip. I will bring 3 airplanes. My electric 576 Ringmaster, my Extra 300S, and my DO-335. Hope to get in some fun flying with the Ringmaster on Friday. I need to learn the novice pattern. Right now I have attempted everything but the overhead 8.
What time does the scale contest begin on Saturday?
Hi John,I think around 8 AM.Allen likes to get things going early.I am going down to Muncie on Thursday to practice and will be glad to help you with that overhead 8 Friday if you would like.I am camping at the AMA so I won't be hard to find.Trax
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Hi John,I think around 8 AM.Allen likes to get things going early.I am going down to Muncie on Thursday to practice and will be glad to help you with that overhead 8 Friday if you would like.I am camping at the AMA so I won't be hard to find.Trax
Trax,
What does you camper look like? Will you be in the RV hookup lot or the camping area? I will also be traveling Thursday. I have a Coleman camper that has been converted to a one room toy hauler. It is no longer a camper but an EZ-UP on wheels. I will probably park it at the L pad. For me ruffing it is a lumpy bed at a motel.
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John,Ill be at the primitive camoground.I have a transistor radio and a flashlight.All the juice I need.I drive a white Dodge Dakota with a cap.
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Well this will be my final post before I head out to the FCM @ AMA. A converted, very old, Coleman camper makes a great toy haler. I have about $600 total in the rig. That includes new wheel hubs (and bearings), new rims, and new tires. It was a ton of work to convert but hay shop time is quality time.
The black covered thing on the front is a 3 KVA generator. The air still works and I have power for charging batteries.
#^ #^ #^
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And a place to sleep when the planes are rearranged it looks like. Have fun at the FCM Contest.
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And a place to sleep when the planes are rearranged it looks like. Have fun at the FCM Contest.
Works for me - BUT the wife needs a motel
LL~ LL~
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Had trouble getting in a test flight - object on the runway!
LL~ LL~ LL~ LL~
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Don't get them upset. I had the same problem flying off an athletic field while attending a company school. But, they would mosey away once I started the engine and once I landed would resume their activity.
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Well the DO-335 is underpowered. I bought a NV AMD 061CL to put in the front. Am bench running it right now. It appears to quit a bit stronger than the TD it will replace.
n~
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Good idea John, but I also think you could use more torque for the rear one to turn all that hardware. I loved watching the ship fly, it is well worth more work!!!!!!!!!!!!!!!!!!!! y1 y1 #^ #^
It was also great to chew the fat and get to know you better.
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Well the DO-335 with a Norvel 061 setup is ready for it's first test flight. The NV AMD 061CL with a Cox 5x3 3-blade, on 30% fuel is turning 20500 RPMs. The back engine, a TD 049 on a Cox 5x3 3-blade pusher and 30% fuel is turning 14000 RPMs. I still have 3 head shims in the AMD 061. But it runs so well that I will try it this way.
Monday is test flight day. Will report.
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Well the DO-335 with a Norvel 061 setup is ready for it's first test flight. The NV AMD 061CL with a Cox 5x3 3-blade, on 30% fuel is turning 20500 RPMs. The back engine, a TD 049 on a Cox 5x3 3-blade pusher and 30% fuel is turning 14000 RPMs. I still have 3 head shims in the AMD 061. But it runs so well that I will try it this way.
Monday is test flight day. Will report.
Good luck with the tests flights, John. It is looking great!
BIG Bear
RNMM/AMM
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It works!! The Norval AMD 061 has great power. The DO-335 is now a contender!
#^
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Awesome John, Good to hear everything worked on the model!
Fred
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Great news, now go get em.
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Excuse my ignorance, but how many laps are required to be flown with all engines running to get the multiple engine bonus?
Thanks!
Bill
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Excuse my ignorance, but how many laps are required to be flown with all engines running to get the multiple engine bonus?
Thanks!
Bill
It depends on the contest. At St Louis all aircraft must be a twin 1/2 A thus no bonus points. It is flown under local rules. I am looking for my copy of rules. They have a minimum number of two engine laps to be an official flight. Not sure how many.
AMA 1/2 A scale rules provides 10 points for up to ten laps (1 point per lap). They also provide 0 to 40 points for realism and smoothness of the flight including the landing.
Their is a five point multi engine bonus "provided the additional engine(s) run during the majority of the flight (excluding landing)"
SO what's the majority of laps. Say if I fly 10 laps - I need 6 laps to qualify. If I fly 20 laps I need 11 to qualify. What I am guessing is that they will quit counting after ten.
FCM goes by AMA rules.
I have no clue on the Texas 1/2 contest.
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Among others I'm anxious to check out this model next weekend. I'm planning on making the trip down from Minnesota, getting to the Pear Tree on Thursday afternoon. ;D
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We talked about the rules at the St Louis club meeting last night. The number of laps came up and the majority vote was 10 laps also.
Give Bob Arata a call (look in the events section for his phone number) and he can give a full run down of the 1/2a rules.
Fred Cronenwett
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That is a great looking plane, super cool!
Steve
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Hi John,
As I have said on other occasions, I think the model is awesome! A very good exercise in "engineering".
I hope to get to see you, and your models, while we are all still around. I think you come up with some great subjects and execute them very nicely.
BIG Bear
RNMM/AMM
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I would love to be able to be there and see this magnificent machine fly. I'm just proud to have been able to contribute to your threads when you were sorting out your engine setup.
Good luck, John.
Rusty
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John,
Didn't see you and the Do335 in St. Louis today. Thought you were coming?
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John,
Didn't see you and the Do335 in St. Louis today. Thought you were coming?
Sorry about that- something came up. Besides he current DO-335 is a lead sled. I have started version 3 - hopefully light enough to fly better. The current one doesn't like wind. Am aiming for next year.
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The new shaft for the 3rd generation DO-335 came in today. It was fabricated by Lee machine shop and it looks great. It has been fitted for a Norval .061 instead of a TD 049. It is 1" longer than the old shaft and weighs less. As always great job Lee! The goal for the third generation DO 335 is weigh 1/2 of what the old one weighs. It also is sporting a new high lift air foil. I am hopping it may possibly do a loop.
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That is a very cool design...
Like it!!!
Just don't forget a vídeo of the new one... ;D ;D
Marcus
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Finally worked out the controls for the elevator. Rear motor shaft is in the way for the normal torsion rod between halves.
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I now have two working 1/2A engines for this project. I picked up a TD .051 for $10 bucks. Rolin picked it up at a swap meet for me. Bench test produced 20K rpm on 25% fuel, 5x3 3 blade Cox prop. Today I built a test stand so I could test run my Norvel .061 driving the U-joint/prop shaft assembly. Bench test also produced 20K rpm on 25% fuel, 5x3 3 blade Cox prop.
#^ #^ #^
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John - Your 1/2a will be in the April 2014 issue of Model Aviation. 1/2a will be covered in the next issue
Like the test stand with the shaft drive
Fred
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John,
Can we see a good close up photo (or photos) of how the shaft is designed at the prop mount?
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John,
Can we see a good close up photo (or photos) of how the shaft is designed at the prop mount?
Attached is the drawing I sent to Lee Machine Shop that was used to create the current shaft. However Lee made the actual shaft from an aluminum tube to save weight.
The prop shown in the test stand picture is a normal prop to provide cooling for the test run. The prop for the airplane is a pusher. On the airplane the rear motor is cooled by prop wash from the front motor.
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John,
Nice design, wish I had thought of something like that.
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Gotta tell ya, John, your engineering skills are fantastic on this. Can't wait to see it fly! #^ #^ #^
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Attached is the drawing I sent to Lee Machine Shop that was used to create the current shaft. However Lee made the actual shaft from an aluminum tube to save weight.
The prop shown in the test stand picture is a normal prop to provide cooling for the test run. The prop for the airplane is a pusher. On the airplane the rear motor is cooled by prop wash from the front motor.
Thanks John. Does it use a stock Cox prop thrust washer or...?
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Thanks John. Does it use a stock Cox prop thrust washer or...?
Yes it is a Cox prop thrust washer. The bearing is from McMaster-Carr. The PN on the package is SRW4ZZ A5. McMaster PN 57155K388. It is a .250 ID, .6250 OD. The outer race is .1960 wide. However the inner race is raised. It is .2272 wide. This allows the bearing's inner race to be hard clamped to the shaft. It is wedged between the prop washer and the shoulder on the shaft. It is double shielded and pre-lubed. However I have had bearing failures until I started adding a drop of oil before each flight. Also they are cheep so I tend to install a new one right before a contest.
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Thanks for the info John, I've been kicking around an idea for a few years for which I would need a reliable shaft setup. I would be needing it for a .15 or a .25 size engine.
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Thanks for the info John, I've been kicking around an idea for a few years for which I would need a reliable shaft setup. I would be needing it for a .15 or a .25 size engine.
The hard part is the U-joint. I bought mine 2 years ago on Ebay. I have been looking and can not find anything listed anywhere comparable in size. Every thing listed today is for small eclectic boats or for flex shafts. The motor side of my joint has a 1/4 x 20 thread. Lee plugged it and re-threaded for the Norval .061 shaft. If anyone knows of a source please list it.
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Nice!!
Marcus
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Thanks for the info John, I've been kicking around an idea for a few years for which I would need a reliable shaft setup. I would be needing it for a .15 or a .25 size engine.
Just for fun I ordered the U-joint I found on eBay.
http://www.ebay.com/itm/380691644809?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
It looks like that it could work with a 15 to 25 size engine. It measures about 1.3" long. The motor side has what appears to be a 5mm x .8 bolt hole. Adapting this to your motor could be interesting. Of course if you have a 5 mm motor shaft all is good. If the motor shaft is smaller you could use an insert. If it is larger it could be a problem. I think the part is hardened steel and would be hard to machine.
The shaft end has a 4 mm hole and a set screw. One would have to machine a shaft end to fit.
If you are serious about getting this to work buy one of the U-joints. Send your motor, U-joint, drive washer, etc to Lee machine shop. I would bet Lee can make it all work.
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Well the bad news is that I trashed the LA-5 again and I will not be attending the NATS. The good news is that the DO-335 is ready for paint. Right now my plans are to attend the the FCM. Hope to bring my Extra 300S (Fun Scale) and the DO-335 for 1/2 A scale. Possibility I may try my hand at beginners stunt.
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I finally have finished the 3rd generation DO-335. In the photo is the family tree of the 3 generations. The small one was first. It was too small. Second one was bigger but too heavy. It didn't want to fly. It had 3 problems: Too heavy, bad airfoil, and elevator on one side only. This leads us to the 3rd generation. 1: is lighter. 2: It has a real airfoil (S7055) extracted from the book Summary of Low-Speed Airfoil Data by the University of Illinois. 3: It has the elevator on both sides.
The test flight one day this week will tell the tail! y1
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More 3rd gen DO-335 photos
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It looks like there's a lot of hard work and craftsmanship in all three planes. Hopefully the 3rd time will be a charm!
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John, can't wait to see it fly.......3 weeks away.
Blessings
Allen
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John that is some piece of work! I mean that in a great way. I bet the Tee Dee uses more gas. My Norvel .061s sip fuel compared to my Tee Dee .049s. So, which engine do you want to shut down first?
Rusty
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John that is some piece of work! I mean that in a great way. I bet the Tee Dee uses more gas. My Norvel .061s sip fuel compared to my Tee Dee .049s. So, which engine do you want to shut down first?
Rusty
That's the beauty of inline twins. It doesn't matter which one quits first. y1
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Well after almost destroying it I finally have it working. The problem was that I couldn't keep the back engine running. To make the long story short I had put a NORVEL AMD 061 on the back. I started out with a balloon tank and then I tried a bladder tank. No matter what I tried it was not a happy camper. I am not sure what the problem is but it appears that the NORVLE AMD does not like reverse air flow over the venture. So as the air blast from the front engine would change the NROVEL would go nuts and quit. You could gets things running OK but on launch the airflow would change and the NORVEL would die. The cure was to put a stock TD with a product engine 049 jug on the back. First test run on the bench and every thing was happy. Fist test flight today both engines ran the full flight (17 laps). By the way the front engine is a TD 051. So Broken Arrow here we come.
PS I may even have my LA-5 back in the air by then.
CLP** CLP** CLP** CLP**
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The DO-335 was dissembled, cleaned, paint touch up, new decals and reassembled. After her many crashes (back engine kept quitting) she is ready for her first static judging! CLP**
More good news the LA-5 is back together, wings are covered, and tomorrow I start the painting process. It too will be ready for Broken Arrow!
Praying for good weather. Hope to see all of you!
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John,
we are getting ready here for the Broken arrow and will be excited to see the DO-335 in person!
Looking forward to seeing you again
Fred
http://lafayetteesquadrillecl.wordpress.com/lafayette-esquadrille-cl/control-line-contest-st-louis/control-line-stunt-pampa-scale-broken-arrow-st-louis/
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Good luck, John!
Rusty
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Sunday, after Church I test flew the LA-5. It has survived all of my abuse! It still flies great. So it's off to Broken Arrow with 3 airplanes: Extra 300S, LA-5, And the DO-335.
Hope we have good weather!
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Knock'em dead, John!!
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John you realize what you have done here? You have upped the anty on 1/2A scale competition. If someone wants to do well in this event you better do your homework, because John has! Great looking airplane. May we see you at the NASA scale classic in a couple weeks?
Hope all goes well this weekend in St.Louis.
Blessings
Allen
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John flew his DO-335 at the Broken arrow, the video not quite in focus but still shows the model flew very well
https://www.youtube.com/watch?v=M03QbwolDhg
Enjoy....great Job John, 2nd place out of 5 entries
Fred Cronenwett
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Fred,
Thanks!!!! y1
A great video of the best flight ever on the DO-335. I actually worked at having the front engine quit first. When it dose I can land and taxi on the back engine. When the front engine stops the back engine has little or no cooling so it heats up goes over lean and slows down. Once on the ground it contentious to slow down until it quits. I will claim that I designed it that way - that it wasn't an accident. Anyway however it came about it is now called a feature.
Thanks to all who put on the Broken arrow Scale contest. I had a blast.
#^ #^ #^ #^ #^ H^^