25% Cessna L-19/0-1 Bird Dog build
03-16-2011, 04:18 PM
#751
RE: 25% Cessna L-19/0-1 Bird Dog build
This manual leaves a lot to be desired unless they have revised it. It should be ok for anyone with a couple of arf builds under their belt. The glue job on the windows is poor I have had to reglue most of them. The blue color on the insignia is wrong. Other than that it appears to be well constructed. If you desire to change color scheme scrub the covering well with fine sandpaper or steel wool as paint does not adhere well to the covering.
Tas
Tas
03-22-2011, 06:32 PM
#752
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RE: 25% Cessna L-19/0-1 Bird Dog build
hi guys just started my 1\4 vailley bird dog wings are framed tail just started i didnt have a computer for a while so i didnt see all the helpfull hints it will take all week to read all of it . i will be posting pics as i go on my blog check it out p.s. hopefully i will get it done for top gun 2012 this year i will be flying my 1\3 scale flybaby bipe n500f in pro am the dog will be in expert
03-22-2011, 07:05 PM
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RE: 25% Cessna L-19/0-1 Bird Dog build
ORIGINAL: tcrowson
This manual leaves a lot to be desired unless they have revised it. It should be ok for anyone with a couple of arf builds under their belt. The glue job on the windows is poor I have had to reglue most of them. The blue color on the insignia is wrong. Other than that it appears to be well constructed. If you desire to change color scheme scrub the covering well with fine sandpaper or steel wool as paint does not adhere well to the covering.
Tas
This manual leaves a lot to be desired unless they have revised it. It should be ok for anyone with a couple of arf builds under their belt. The glue job on the windows is poor I have had to reglue most of them. The blue color on the insignia is wrong. Other than that it appears to be well constructed. If you desire to change color scheme scrub the covering well with fine sandpaper or steel wool as paint does not adhere well to the covering.
Tas
08-04-2011, 10:33 AM
#754
RE: 25% Cessna L-19/0-1 Bird Dog build
OK, finally back and working toward finishing the DAWG for our September Warbird meet held at our Maryland field (PGRC). The DAWG will be finished in South Vietnam Air Force colors. Will post pictures soon. The Avenger will be placed to the side until the DAWG is done. Curtis, tried to answer your email, give me a call 703-768-6347, would love to have ya come by. Chic
08-04-2011, 10:46 AM
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RE: 25% Cessna L-19/0-1 Bird Dog build
It's about time!!!! Too hot to actually fly much so might as well sit around and build. 
Me? Well, my workshop is at the moment being torn down. The replacement will be way nicer. I have stuff stuck all over the house and am yet again testing the patience of my better half. But, she gets her garden tool side shed in the process and a much better looking building, so all good on that front so far.
And, Redtail.... I've gotten back to my Merlyn and coming down the home stretch on that project. Have made a decision about the next step on my SR-10, so it will no longer be in snagged state and I'm starting to get really anxious to start that P-47, which at the moment, I'm thinking I'll go ahead with the aluminum covering and then the paint scheme. Those look so very nice. And, after that, I really want to do one of these Bird Dogs and had been sort of waiting on the 1/3rd scale which I see is out. I suppose it could easily act as a tug for the Merlyn.
I'm looking forward to more photos of your Bird Dog. You are a true craftsman!
Me? Well, my workshop is at the moment being torn down. The replacement will be way nicer. I have stuff stuck all over the house and am yet again testing the patience of my better half. But, she gets her garden tool side shed in the process and a much better looking building, so all good on that front so far.
And, Redtail.... I've gotten back to my Merlyn and coming down the home stretch on that project. Have made a decision about the next step on my SR-10, so it will no longer be in snagged state and I'm starting to get really anxious to start that P-47, which at the moment, I'm thinking I'll go ahead with the aluminum covering and then the paint scheme. Those look so very nice. And, after that, I really want to do one of these Bird Dogs and had been sort of waiting on the 1/3rd scale which I see is out. I suppose it could easily act as a tug for the Merlyn.
I'm looking forward to more photos of your Bird Dog. You are a true craftsman!
01-11-2012, 03:59 AM
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RE: 25% Cessna L-19/0-1 Bird Dog build
Hi All,
Is anyone actively building / flying the L-19 at this time?I'm wondering whatthe build time is, man hours wise. This is a great resource!
Is anyone actively building / flying the L-19 at this time?I'm wondering whatthe build time is, man hours wise. This is a great resource!
01-11-2012, 04:26 AM
#758
RE: 25% Cessna L-19/0-1 Bird Dog build
Smoothride, I'm still working on my DAWG, however, I have had some personal problems which kept me away from the build. My DAWG is fully built, completely primered and now ready to sand, paint, and reinstall the radio equip. If you stick with the build, it could be a 4 month to a year build depending on the scale details you wish to construct. Chic
01-13-2012, 04:19 PM
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RE: 25% Cessna L-19/0-1 Bird Dog build
Thanks Redtail,
Hope the New Year is going well, and hope you are able to finish the build, but most of all that you remain healthy and happy.
I find the Bird Dog a fascinating subject for some unexplained reason (Maybe it all started whenI built a small guillows model as a kidbalsa and tissue). Now I'm fully grown up, and since I can't afford a real one, this is the next best thing. I may go to Wurtsburough, NY (which has an L-19) to take a fewhops with a CFIfor a taildragger endorsement at some pointwhat a way to get a taildragger qual! The rental fees there are pretty cheapalmost to the point where I wonder if they are correct?
I read about the Raven FACs in Laos as a kid also, and developed a great appreciation of O-1/L-19s from the stories of AirForce guysflying out of small airstrips in the misty jungle. I have a whole lot of respect for them and the other FACs I read about. Just today a buddy at work (Harrier guy) was telling me about his experience acting as a FAC, but also relating stories of his Dad in Vietnam flying an A-4. I was a Navy P-3 pilot, and only acted in some small capacity as a sort of FAC when vectoring helicopters to kill submarines (exercises etc...)or for search and rescue ops. It is busy work indeed, you end up writing with a grease pencil on the canopy/cockpit plexiglassall the frequencies and call signs, weapons loads, fuel until splash, etc... Very fulfilling though.
Must run now, all my best!
Matt
Hope the New Year is going well, and hope you are able to finish the build, but most of all that you remain healthy and happy.
I find the Bird Dog a fascinating subject for some unexplained reason (Maybe it all started whenI built a small guillows model as a kidbalsa and tissue). Now I'm fully grown up, and since I can't afford a real one, this is the next best thing. I may go to Wurtsburough, NY (which has an L-19) to take a fewhops with a CFIfor a taildragger endorsement at some pointwhat a way to get a taildragger qual! The rental fees there are pretty cheapalmost to the point where I wonder if they are correct?
I read about the Raven FACs in Laos as a kid also, and developed a great appreciation of O-1/L-19s from the stories of AirForce guysflying out of small airstrips in the misty jungle. I have a whole lot of respect for them and the other FACs I read about. Just today a buddy at work (Harrier guy) was telling me about his experience acting as a FAC, but also relating stories of his Dad in Vietnam flying an A-4. I was a Navy P-3 pilot, and only acted in some small capacity as a sort of FAC when vectoring helicopters to kill submarines (exercises etc...)or for search and rescue ops. It is busy work indeed, you end up writing with a grease pencil on the canopy/cockpit plexiglassall the frequencies and call signs, weapons loads, fuel until splash, etc... Very fulfilling though.
Must run now, all my best!
Matt
01-13-2012, 05:00 PM
#760
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RE: 25% Cessna L-19/0-1 Bird Dog build
I know this is not specifically on the subject but this forum inspired me to develop my Bird Dog. I thought you guys might be interested. I finished the 1/3 scale Bird Dog design and build late last year and it is a great flying airplane. She is modeled after one of the US Army's 73rd Aviation FAC groups in Vietnam around 1963.
Powered by a DLE-111 at 59 pounds she really floats. The whole design and build is posted on RCSB.
http://www.rcscalebuilder.com/forum/...TID=15387&PN=1
Here is a video of the Bird Dog during our October IMAA Fly In. Ugly first landing but the second is OK. You have to use flaps on this airplane.
http://www.youtube.com/watch?v=2LHZt-bOBI0
Powered by a DLE-111 at 59 pounds she really floats. The whole design and build is posted on RCSB.
http://www.rcscalebuilder.com/forum/...TID=15387&PN=1
Here is a video of the Bird Dog during our October IMAA Fly In. Ugly first landing but the second is OK. You have to use flaps on this airplane.
http://www.youtube.com/watch?v=2LHZt-bOBI0
01-13-2012, 08:30 PM
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RE: 25% Cessna L-19/0-1 Bird Dog build
Ricmod5634 1/5 Roy dowg. Guy's I might actully finish mine this winter. Starting to feel a little better and getting tired of my better half telling me to get off my , you know what. That and having a Balsa USA 1/4 Cub started and sitting on the table. And then there's the guys at the club looking forward to seeing them at our annual Big Bird FlyIn. Glad to see this tread is still around and being used.
Rich
Rich
01-14-2012, 05:57 AM
#763
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RE: 25% Cessna L-19/0-1 Bird Dog build
ORIGINAL: redtail
Gsmith, a great build, beautiful work. Certainly give you a 9 on that second landing, trust me, we have all had a similar landing as your first. Great hearing from ya. Chic
Gsmith, a great build, beautiful work. Certainly give you a 9 on that second landing, trust me, we have all had a similar landing as your first. Great hearing from ya. Chic
Thanks for the 9. The Dawg will make perfect landings...it's the pilot that needs practice:-)
Gaines
01-14-2012, 07:50 AM
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RE: 25% Cessna L-19/0-1 Bird Dog build
GSMITH,
That is amazing59 Lbs? Unreal. It behaves pretty closely to afull scale airplane. What a work of art! Thereis suchan array ofhighly detailed models displaying trulyprodigous workmanship on this thread, I am again, amazed.
I think the 1/4 scale birds were coming in at about 25-29 lbs or so?
Iam in a strange mood this morning, probably too much caffeine, so if you are really boredhere is what was playing with: (SORRYTHISISSOLONG)
Beingcurious about theweights ofafull scaleO-1/L-19 compared to scaled down models, and also comparing weights of both 1/3rd scale and 1/4scale L19s,I found:
Thefull scalemax gross weight of an O-1Eis about 2400 lbs minus 340 lbs (2 people per FAA average human weight of 170 lbs) is 2060 lbsfor an E model. A quarter scale human would be about 40 lbs,so I disregarded that (got rid of it). The weight of 2060 lbsdivided by 4 (25%) would be about 515 lbs. So a 1/4 scale O-1E model true to scale weightwould beabout 515 lbs approximately. Most O-1/L-19 1/4 scale models are approx. 27 lbs. So balsa and fiberglass (?) model airplanes are much lighter than true scale counterparts (made of different materials, heavier power plant, morefuel,payloadetc....). This is for a reason though. Take the fuel example for instance; O-1E max useable fuel is approx 40 gallons. This is about 240 lbs of fuel. The full scaleL-19 burns about 10 gal per hour roughly, giving an endurance of about 4 hours. Scaled down, again, by 25% would mean that a 25% scale model should have an endurance of 1 hour. Does anyone want to have a 1/4 scale L-19 that flies around for an hour?
Ok, I didn't know there was such a scale disparity between RC airplanes and full scale airplanes regarding weight(never thought about it I guess).
Next I wondered about comparing the weight of a 1/3 scale model compared to a 1/4 scale model. Were the weights proportional? See below to find out->
That is amazing59 Lbs? Unreal. It behaves pretty closely to afull scale airplane. What a work of art! Thereis suchan array ofhighly detailed models displaying trulyprodigous workmanship on this thread, I am again, amazed.
I think the 1/4 scale birds were coming in at about 25-29 lbs or so?
Iam in a strange mood this morning, probably too much caffeine, so if you are really boredhere is what was playing with: (SORRYTHISISSOLONG)
Beingcurious about theweights ofafull scaleO-1/L-19 compared to scaled down models, and also comparing weights of both 1/3rd scale and 1/4scale L19s,I found:
Thefull scalemax gross weight of an O-1Eis about 2400 lbs minus 340 lbs (2 people per FAA average human weight of 170 lbs) is 2060 lbsfor an E model. A quarter scale human would be about 40 lbs,so I disregarded that (got rid of it). The weight of 2060 lbsdivided by 4 (25%) would be about 515 lbs. So a 1/4 scale O-1E model true to scale weightwould beabout 515 lbs approximately. Most O-1/L-19 1/4 scale models are approx. 27 lbs. So balsa and fiberglass (?) model airplanes are much lighter than true scale counterparts (made of different materials, heavier power plant, morefuel,payloadetc....). This is for a reason though. Take the fuel example for instance; O-1E max useable fuel is approx 40 gallons. This is about 240 lbs of fuel. The full scaleL-19 burns about 10 gal per hour roughly, giving an endurance of about 4 hours. Scaled down, again, by 25% would mean that a 25% scale model should have an endurance of 1 hour. Does anyone want to have a 1/4 scale L-19 that flies around for an hour?
Ok, I didn't know there was such a scale disparity between RC airplanes and full scale airplanes regarding weight(never thought about it I guess).
Next I wondered about comparing the weight of a 1/3 scale model compared to a 1/4 scale model. Were the weights proportional? See below to find out->
- [*]The 1/3 scale = 59 lbs //// the 1/4 scale= 27 lbs (I used 27 lbs which was the middle of 25-29 lbs for kicks)[*]59 lbs / .333 scale= 177////27 lbs/ .25 scale= 108(Ratios comparingweight to scale) using 1/3 scale = .333 1/4 scale = .25[*]Reduced to:3.54/// 2.16 (Proportion of the two numbers) 3.54 / 2.16 = 1.64[/list]So I think this means that the 1/3rd scale L-19 is 1.64 timesheavier in proportion tothe 1/4 scale version at higher weights; and I checked the lighter gross weights for scale on the Vailly website (1/3 scale = 40lbs, and 1/4 scale = 19lbs)and came up with 1.66-you can call this a sensativity analysis which was not very sensative
for weight, makes sense. I think most builders come in heavier probably due to wanting super detail for aesthetics and a beefed up structure using fiberglass or some other material for durability/survivability. It shows that the larger scale RC airplanes are heavier comparable to smaller scale ones. In this case an 8.3% increase in scale resulted in an airplane that was 2.19 times heavier. Thoughts / Sanity check?Matt
01-14-2012, 08:14 AM
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RE: 25% Cessna L-19/0-1 Bird Dog build
Matt,
You seem to be doing your math in a linier fashion; ie 1/4 of 12" equals 3", 1/4 of 100 lbs equals 25 lbs. I think you would need to account for the volume as well, ie 1/4 of 1 cubic foot (12'' x 12'' x 12'' equals 1728 Cubic inches) is 432 cu", but 3" x 3" x 3" is only 27 cu", a big difference.
.
You seem to be doing your math in a linier fashion; ie 1/4 of 12" equals 3", 1/4 of 100 lbs equals 25 lbs. I think you would need to account for the volume as well, ie 1/4 of 1 cubic foot (12'' x 12'' x 12'' equals 1728 Cubic inches) is 432 cu", but 3" x 3" x 3" is only 27 cu", a big difference.
.
01-14-2012, 09:45 AM
#767
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RE: 25% Cessna L-19/0-1 Bird Dog build
ORIGINAL: smoothride
GSMITH,
That is amazing59 Lbs? Unreal. It behaves pretty closely to a full scale airplane. What a work of art! There is such an array of highly detailed models displaying truly prodigous workmanship on this thread, I am again, amazed.
I think the 1/4 scale birds were coming in at about 25-29 lbs or so?
I am in a strange mood this morning, probably too much caffeine, so if you are really boredhere is what was playing with: (SORRY THIS IS SO LONG)
Being curious about the weights of a full scale O-1/L-19 compared to scaled down models, and also comparing weights of both 1/3rd scale and 1/4 scale L19s, I found:
The full scale max gross weight of an O-1E is about 2400 lbs minus 340 lbs (2 people per FAA average human weight of 170 lbs) is 2060 lbs for an E model. A quarter scale human would be about 40 lbs, so I disregarded that (got rid of it). The weight of 2060 lbs divided by 4 (25%) would be about 515 lbs. So a 1/4 scale O-1E model true to scale weight would be about 515 lbs approximately. Most O-1/L-19 1/4 scale models are approx. 27 lbs. So balsa and fiberglass (?) model airplanes are much lighter than true scale counterparts (made of different materials, heavier power plant, more fuel, payload etc....). This is for a reason though. Take the fuel example for instance; O-1E max useable fuel is approx 40 gallons. This is about 240 lbs of fuel. The full scale L-19 burns about 10 gal per hour roughly, giving an endurance of about 4 hours. Scaled down, again, by 25% would mean that a 25% scale model should have an endurance of 1 hour. Does anyone want to have a 1/4 scale L-19 that flies around for an hour?
Ok, I didn't know there was such a scale disparity between RC airplanes and full scale airplanes regarding weight (never thought about it I guess).
Next I wondered about comparing the weight of a 1/3 scale model compared to a 1/4 scale model. Were the weights proportional? See below to find out->
GSMITH,
That is amazing59 Lbs? Unreal. It behaves pretty closely to a full scale airplane. What a work of art! There is such an array of highly detailed models displaying truly prodigous workmanship on this thread, I am again, amazed.
I think the 1/4 scale birds were coming in at about 25-29 lbs or so?
I am in a strange mood this morning, probably too much caffeine, so if you are really boredhere is what was playing with: (SORRY THIS IS SO LONG)
Being curious about the weights of a full scale O-1/L-19 compared to scaled down models, and also comparing weights of both 1/3rd scale and 1/4 scale L19s, I found:
The full scale max gross weight of an O-1E is about 2400 lbs minus 340 lbs (2 people per FAA average human weight of 170 lbs) is 2060 lbs for an E model. A quarter scale human would be about 40 lbs, so I disregarded that (got rid of it). The weight of 2060 lbs divided by 4 (25%) would be about 515 lbs. So a 1/4 scale O-1E model true to scale weight would be about 515 lbs approximately. Most O-1/L-19 1/4 scale models are approx. 27 lbs. So balsa and fiberglass (?) model airplanes are much lighter than true scale counterparts (made of different materials, heavier power plant, more fuel, payload etc....). This is for a reason though. Take the fuel example for instance; O-1E max useable fuel is approx 40 gallons. This is about 240 lbs of fuel. The full scale L-19 burns about 10 gal per hour roughly, giving an endurance of about 4 hours. Scaled down, again, by 25% would mean that a 25% scale model should have an endurance of 1 hour. Does anyone want to have a 1/4 scale L-19 that flies around for an hour?
Ok, I didn't know there was such a scale disparity between RC airplanes and full scale airplanes regarding weight (never thought about it I guess).
Next I wondered about comparing the weight of a 1/3 scale model compared to a 1/4 scale model. Were the weights proportional? See below to find out->
- [*]The 1/3 scale = 59 lbs //// the 1/4 scale = 27 lbs ( I used 27 lbs which was the middle of 25-29 lbs for kicks) [*]59 lbs / .333 scale = 177 //// 27 lbs / .25 scale = 108 ( Ratios comparing weight to scale ) using 1/3 scale = .333 1/4 scale = .25 [*]Reduced to: 3.54 /// 2.16 (Proportion of the two numbers) 3.54 / 2.16 = 1.64[/list] So I think this means that the 1/3rd scale L-19 is 1.64 times heavier in proportion to the 1/4 scale version at higher weights; and I checked the lighter gross weights for scale on the Vailly website (1/3 scale = 40lbs, and 1/4 scale = 19lbs) and came up with 1.66-you can call this a sensativity analysis which was not very sensative [img][/img] for weight, makes sense. I think most builders come in heavier probably due to wanting super detail for aesthetics and a beefed up structure using fiberglass or some other material for durability/survivability. It shows that the larger scale RC airplanes are heavier comparable to smaller scale ones. In this case an 8.3% increase in scale resulted in an airplane that was 2.19 times heavier. Thoughts / Sanity check?
Matt
Thanks for the compliment. Scale detail adds weight but the big Bird Dog doesn't know it is bit pudgy:-)
Your calculations are all probably correct but there is very little relevance in trying to do this math with our scale models. The 1/4 scale Bird Dog will fly great at 25-29 pounds. My 1/3 scale also flies great at 59 pounds. The larger scale models will fly well at higher wings loadings that the smaller scale models.
Just for the record the estimated weight for the Vailly 1/3 scale Bird Dog is 40-60 pounds. It probably could be built at 40 pounds but it will take a much better builder than me.
From the website:
1/3 Scale
Wingspan ............... 147 in ........... Wing Area ................ 2305 sq.in
Overall Length .......... 97 in .......... . Weight ...................... 40 - 60 Lbs
Engine ..................... Zenoah GT-80 minimum, Any 150 cc twin !
01-14-2012, 10:07 AM
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RE: 25% Cessna L-19/0-1 Bird Dog build
Hi Skylarkmk1,
Yup, you are right,linear was all I could think of after waking up earlier (not enough coffee).I was only able to do the linear relationship of weight vs scale.
But you bring upa fun thingto research (ok, maybe fun is a stretch, but it is interesting).Volume of a bird dog may be a littlehard to figure out thoughand would not be exact (no way of figuring that outwithout an actual example, tape measure, and lots of free time).But maybe measuring the 1/4 scalebird dog planswith a planimeter for area, then figure out volumeand scalingup might workbut I don't have plans yet (plus that's tedious).
I was thinking of checking outwing loadinga published number for airplanes, and easy to figure out as well if you don't have it. It would probablyoffer a little insightas to why airplanes (full scale or any scale) that have light wing loadings get thrown around in any kind of turbulence, while aircraft with heavier wing loadings don't. It would alsoshow why smaller scaleRC models don't behave the same way in theair with such lightwing loadings.
Thanks for the insight!
Matt
Yup, you are right,linear was all I could think of after waking up earlier (not enough coffee).I was only able to do the linear relationship of weight vs scale.
But you bring upa fun thingto research (ok, maybe fun is a stretch, but it is interesting).Volume of a bird dog may be a littlehard to figure out thoughand would not be exact (no way of figuring that outwithout an actual example, tape measure, and lots of free time).But maybe measuring the 1/4 scalebird dog planswith a planimeter for area, then figure out volumeand scalingup might workbut I don't have plans yet (plus that's tedious).
I was thinking of checking outwing loadinga published number for airplanes, and easy to figure out as well if you don't have it. It would probablyoffer a little insightas to why airplanes (full scale or any scale) that have light wing loadings get thrown around in any kind of turbulence, while aircraft with heavier wing loadings don't. It would alsoshow why smaller scaleRC models don't behave the same way in theair with such lightwing loadings.
Thanks for the insight!
Matt
01-14-2012, 10:12 AM
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RE: 25% Cessna L-19/0-1 Bird Dog build
Oh, Hi GSmith,
I had just posted this and saw your commentgreat minds think alike!!
Seriously, that is one beautiful airplane that you made!
And thanks for the info which I will go look at compared to the full scale. I'm interested in the 1/4 scale Vailly model. This forum will be a great resource.
Cheers,
Matt
I had just posted this and saw your commentgreat minds think alike!!
Seriously, that is one beautiful airplane that you made!
And thanks for the info which I will go look at compared to the full scale. I'm interested in the 1/4 scale Vailly model. This forum will be a great resource.
Cheers,
Matt
01-14-2012, 12:06 PM
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RE: 25% Cessna L-19/0-1 Bird Dog build
ORIGINAL: smoothride
Oh, Hi GSmith,
I had just posted this and saw your commentgreat minds think alike!!
Seriously, that is one beautiful airplane that you made!
And thanks for the info which I will go look at compared to the full scale. I'm interested in the 1/4 scale Vailly model. This forum will be a great resource.
Cheers,
Matt
Oh, Hi GSmith,
I had just posted this and saw your commentgreat minds think alike!!
Seriously, that is one beautiful airplane that you made!
And thanks for the info which I will go look at compared to the full scale. I'm interested in the 1/4 scale Vailly model. This forum will be a great resource.
Cheers,
Matt
The Vailly 1/4 scale Bird Dog will build into a very nice flying airplane. I chose to design my 1/3 scale to get a more scale design and I like to design in cad. I noticed after I posted Vailly's specs that he lists the wing span as 147". The full scale is 36 feet which comes out at 144" (12 feet) for 1/3 scale. I don't know where Roy came up with the extra 3".
Gaines
01-14-2012, 03:02 PM
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RE: 25% Cessna L-19/0-1 Bird Dog build
I bought a Vailly 1/5scale L19 on RCU this summer.Looks like a well built plane.It has a Zenoah 23 in it,this plane is heavy.Is this enough engine.The next thing that worries me is the wings do not have a spar or a wing tube they bolt on to the top of the fuse then appear to be supported by the wing struts. Will these hold up in flight or is this an inflight break up comming? Anyone know anything about these planes that can give me some assurences that this L19 is flight worthy.
01-14-2012, 03:48 PM
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RE: 25% Cessna L-19/0-1 Bird Dog build
here is my 1/4 birddog. mine came out at 28lbs. have a ralph cunningham G-62 LITE on the front of this with a 24-8 menz prop..this airplane has WAY more than enough power with this engine- prop combo.once in the air it flies like a mild sport plane...i still have to tone down the rudder some as you can see in this posted video of a dramatic takeoff....yes we all have them...lol...a very nice plane to fly...SCALEMAN,.... yes these are working scale struts on this airplane so make sure they are up for the task.
http://www.youtube.com/watch?v=pYXCm...76FAAAAAAAAIAA
http://www.youtube.com/watch?v=pYXCm...76FAAAAAAAAIAA
01-14-2012, 06:39 PM
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RE: 25% Cessna L-19/0-1 Bird Dog build
With regard to the scaled weight of our scale models, the "correct" way of calculating is like this.
For a 1:3 scale model.
Weight is divided by 3x3x3=27
Area is divided by: 3x3=9
For a 1:4 scale model
Weight is divided by 4x4x4=64
Area is divided by: 4x4=16
Going with the example mentioned earlier we get
1:1 scale model
Weight: 2400lb
Wing area (according to Wiki): 174ft²
Wing loading: 13,8lb/ft²
1:3 scale model:
Weight: 88,88lb
Wing area: 19,33ft²
Wing loading: 4,59lb/ft²
1:4 scale model:
Weight: 37,50lb
Wing area: 10,87ft²
Wing loading: 3,44lb/ft²
What I have found is, that instead of using the cubed scale factor (scale^3), I use (scale^3,5), and get results a bit closer to the normal numbers for the 1:3 scale models I prefer.
This gives the following numbers
1:3 scale
Weight: 51,32lb
Wing area: 19,33ft²
Wing loading: 2,65lb/ft²
1:4 scale
Weight: 18,75lb
Wing area: 10,87ft²
Wing loading: 1,72lb/ft²
As can be seen from the above, the numbers "fits" the 1:3 scale model the best, while the smaller 1:4 models normally builds heavier than predicted by this.
For a 1:3 scale model.
Weight is divided by 3x3x3=27
Area is divided by: 3x3=9
For a 1:4 scale model
Weight is divided by 4x4x4=64
Area is divided by: 4x4=16
Going with the example mentioned earlier we get
1:1 scale model
Weight: 2400lb
Wing area (according to Wiki): 174ft²
Wing loading: 13,8lb/ft²
1:3 scale model:
Weight: 88,88lb
Wing area: 19,33ft²
Wing loading: 4,59lb/ft²
1:4 scale model:
Weight: 37,50lb
Wing area: 10,87ft²
Wing loading: 3,44lb/ft²
What I have found is, that instead of using the cubed scale factor (scale^3), I use (scale^3,5), and get results a bit closer to the normal numbers for the 1:3 scale models I prefer.
This gives the following numbers
1:3 scale
Weight: 51,32lb
Wing area: 19,33ft²
Wing loading: 2,65lb/ft²
1:4 scale
Weight: 18,75lb
Wing area: 10,87ft²
Wing loading: 1,72lb/ft²
As can be seen from the above, the numbers "fits" the 1:3 scale model the best, while the smaller 1:4 models normally builds heavier than predicted by this.
01-15-2012, 12:14 AM
#774
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Join Date: Jan 2012
Location: King George, VA
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RE: 25% Cessna L-19/0-1 Bird Dog build
Pelle,
That's good info, thanks for writing it all down!
What models have you made or flown in 1/3 scale?
What models have you made or flown in 1/3 scale?
Gaines,
Not sure why Roy had the extra wingspan added to the design.I believe that the little C-172 has a 36 foot wingspan, and the O-1 was derived from that.It's a really light wing loading (14 lbs/ft<sup>2</sup>), compared to a Cirrus SR-22, for example,at 23.5 lbs/ft<sup>2</sup> and handles turbulence better than a 172,it's noticeable.
I'm pretty sure that my theoretical 1/4 bird dog will end up weighing more towards the high end of the scale (I don't have half the modeling skill that you do).
Gblas,
That is animpressive and sturdy looking airplane, it's remarkable how close to full scale it can look when flying / on the grass field.Amazing job!
It's easy to see how much zeal and enthusiasm, not to mention skill,all of you have with your airplanes in this forum.It's a good thing that those of you that did this before me have made such a nice resource!It is much appreciated, and motivating!
Matt
01-15-2012, 08:41 AM
#775
Join Date: Feb 2002
Location: Billund, DENMARK
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RE: 25% Cessna L-19/0-1 Bird Dog build
Flying.
Wendell Hostetler 1:3 scale Piper PA-22 Tri-Pacer.
This weighs in at 37lb, and is powered by a G-62.
Using the above mentioned formula this takeoff weight matches a full size Tri-Pacer with two persons onboard. :-)
http://www.youtube.com/watch?v=YmxEUtObisk
Under maintanence.
Toni Clark 1:3 scale Pitts Special S1-S.
This is a little lighter than predicted, weighing in at around 19lb. The formula predicts around 22lb.
It´s also powered by a G-62, but I may install my GT-80 instead to be able to drive a little more prop.
Building.
Frisch Modellbau 1:3 PZL-104 Wilga.
This is to be powered by a german King 140 twin, and I expect a takeoff weight around 52lb, which matches the formula quite well.
Wendell Hostetler 1:3 scale Piper PA-22 Tri-Pacer.
This weighs in at 37lb, and is powered by a G-62.
Using the above mentioned formula this takeoff weight matches a full size Tri-Pacer with two persons onboard. :-)
http://www.youtube.com/watch?v=YmxEUtObisk
Under maintanence.
Toni Clark 1:3 scale Pitts Special S1-S.
This is a little lighter than predicted, weighing in at around 19lb. The formula predicts around 22lb.
It´s also powered by a G-62, but I may install my GT-80 instead to be able to drive a little more prop.
Building.
Frisch Modellbau 1:3 PZL-104 Wilga.
This is to be powered by a german King 140 twin, and I expect a takeoff weight around 52lb, which matches the formula quite well.