Building a Phil Kraft Kwik-Fli Mark III
02-22-2008, 02:27 AM
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Building a Phil Kraft Kwik-Fli Mark III
Hi there,
I'm building a Phil Kraft Kwik-Fli Mark III. The plans I'm using are made by Richard Browning and are available on: [link=http://plans.rcmodell.hu/index.html]plans.rcmodell.hu[/link].
I have started building around october 2007 and have had regular contact with Richard Browning. He has been very very helpful. He mentioned someone from Holland in [link=http://www.rcuniverse.com/forum/m_6591207/anchors_6591207/mpage_1/key_kwik/anchor/tm.htm#6591207]a post he made on this forum[/link]. Well, that's me.
At his request I'm doing a build thead in English on this forum. This forum has a lot of threads on the Kwik-Fli so I won't start with a short historic overview as I did in the my original build thread on the Dutch forum. Just pictures and comments
.
I'm not an experienced RC airplane builder, this is only the second plane I'm building. The first one was a Sig Kadet LT-40. I really enjoyed building the Kadet, so after I did my RC flying exam I started looking for something new to build. Off course the Sig 4* was one of the candidates, it is very popular over here. But I wanted something a little different and my instructor suggested the Kwik-Fli. I thought it looked great and scratch building appealed to me.
The german FMT magazin has a big collection of drawings you can order. They also have a Kwik-Fli drawing, but this seems to be an older version, just look at the nose:
The nose in Richard Brownings CAD drawings looks like this:
I decided to build according to Richard's plans. The FMT magazine's version has different lines for different versions, which is a little confusing.
I'm building a Phil Kraft Kwik-Fli Mark III. The plans I'm using are made by Richard Browning and are available on: [link=http://plans.rcmodell.hu/index.html]plans.rcmodell.hu[/link].
I have started building around october 2007 and have had regular contact with Richard Browning. He has been very very helpful. He mentioned someone from Holland in [link=http://www.rcuniverse.com/forum/m_6591207/anchors_6591207/mpage_1/key_kwik/anchor/tm.htm#6591207]a post he made on this forum[/link]. Well, that's me.
At his request I'm doing a build thead in English on this forum. This forum has a lot of threads on the Kwik-Fli so I won't start with a short historic overview as I did in the my original build thread on the Dutch forum. Just pictures and comments
.I'm not an experienced RC airplane builder, this is only the second plane I'm building. The first one was a Sig Kadet LT-40. I really enjoyed building the Kadet, so after I did my RC flying exam I started looking for something new to build. Off course the Sig 4* was one of the candidates, it is very popular over here. But I wanted something a little different and my instructor suggested the Kwik-Fli. I thought it looked great and scratch building appealed to me.
The german FMT magazin has a big collection of drawings you can order. They also have a Kwik-Fli drawing, but this seems to be an older version, just look at the nose:
The nose in Richard Brownings CAD drawings looks like this:
I decided to build according to Richard's plans. The FMT magazine's version has different lines for different versions, which is a little confusing.
02-22-2008, 05:47 AM
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RE: Building a Phil Kraft Kwik-Fli Mark III
Hi Captain,
I would love to see your build thread. I've got the VTH plans as well but IMO they are crap. An interesting article came with them, but as you wrote, they show mainly Mark I and II. There are only dashed lines for the different empennage outlines of Mk III, and the rest is plain wrong.
Mark III has the smaller Mark II wing (60x11in), but an elongated tail moment arm, the rudder stretched down to the fuselage bottom, the elevator divided to make this possible, and a lower engine thrust line. These modifications are all essential.
The correct Mark III plans seem to be still available from [link=http://www.modelairplanenews.com/]Model Airplane News magazine[/link] (see under Shop-Plans-Planes-Sport, page 3). I don't have these plans but I'd bet they are correct.
Now it would be nice to see your build using Richard Browning's plans because he somewhat "modernized" them. It's quite easy to replace the old servos and linkages by modern ones, even to replace the aileron bellcrank linkage by two separate aileron servos. But it's quite hard to replace the old engine and backplate mount by a modern engine and a T-mount.
I would take a modern .40 engine for it's small size and weight. It has even 1 kW power as opposed to the 1 hp of the old .60 engines. And it may fit into the small nose without setting the firewall backwards and without requiring tail weight for balance.
By the way, I would balance on the main spar in the first place. That gives a rather stable setup which may be pleasant for beginning. It requires up to 0.5 degrees wing incidence, as mentioned in the build articles. You may later set the c/g back to more than 5" behing the leading edge and reduce incidence to nearly zero. You should take measures to be able to adjust the wing incidence and the c/g for this reason. No engine right or down thrust is needed or recommended.
I attach a Mark III plan from a magazine where all dimensions are given so you may check the correctness of your build.
Good luck for your build!
I would love to see your build thread. I've got the VTH plans as well but IMO they are crap. An interesting article came with them, but as you wrote, they show mainly Mark I and II. There are only dashed lines for the different empennage outlines of Mk III, and the rest is plain wrong.
Mark III has the smaller Mark II wing (60x11in), but an elongated tail moment arm, the rudder stretched down to the fuselage bottom, the elevator divided to make this possible, and a lower engine thrust line. These modifications are all essential.
The correct Mark III plans seem to be still available from [link=http://www.modelairplanenews.com/]Model Airplane News magazine[/link] (see under Shop-Plans-Planes-Sport, page 3). I don't have these plans but I'd bet they are correct.
Now it would be nice to see your build using Richard Browning's plans because he somewhat "modernized" them. It's quite easy to replace the old servos and linkages by modern ones, even to replace the aileron bellcrank linkage by two separate aileron servos. But it's quite hard to replace the old engine and backplate mount by a modern engine and a T-mount.
I would take a modern .40 engine for it's small size and weight. It has even 1 kW power as opposed to the 1 hp of the old .60 engines. And it may fit into the small nose without setting the firewall backwards and without requiring tail weight for balance.
By the way, I would balance on the main spar in the first place. That gives a rather stable setup which may be pleasant for beginning. It requires up to 0.5 degrees wing incidence, as mentioned in the build articles. You may later set the c/g back to more than 5" behing the leading edge and reduce incidence to nearly zero. You should take measures to be able to adjust the wing incidence and the c/g for this reason. No engine right or down thrust is needed or recommended.
I attach a Mark III plan from a magazine where all dimensions are given so you may check the correctness of your build.
Good luck for your build!
02-22-2008, 07:19 AM
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RE: Building a Phil Kraft Kwik-Fli Mark III
Oops,
I forgot to mention something. This build thread is more like a copy of the original Dutch thread. I have been building since october 2007 and although I don't go very fast, I did make steady progress. My wing is almost finished, just need to finish the tip, ailerons and servo mounts. I'm currently working on the fuselage.
I'll try to catch up with the Dutch forum over the next days. Lot of typing to do. Also, the way this forum usually handles images is different, so I'll have to upload them here too.
For those who cannot wait, you can try this babelfish'ed URL and see on the last page my current progress:
[link=http://babelfish.altavista.com/babelfish/trurl_pagecontent?lp=nl_en&url=http%3A%2F%2Fwww.modelbouwforum.nl%2Fforums%2F bouwverslagen-vliegen%2F47575-bouwverslag-phil-kraft-kwik-fli-mk-iii.html]Babelfish translation of Dutch original[/link]
I have seen that the results are hilarious sometimes...
I forgot to mention something. This build thread is more like a copy of the original Dutch thread. I have been building since october 2007 and although I don't go very fast, I did make steady progress. My wing is almost finished, just need to finish the tip, ailerons and servo mounts. I'm currently working on the fuselage.
I'll try to catch up with the Dutch forum over the next days. Lot of typing to do. Also, the way this forum usually handles images is different, so I'll have to upload them here too.
For those who cannot wait, you can try this babelfish'ed URL and see on the last page my current progress:
[link=http://babelfish.altavista.com/babelfish/trurl_pagecontent?lp=nl_en&url=http%3A%2F%2Fwww.modelbouwforum.nl%2Fforums%2F bouwverslagen-vliegen%2F47575-bouwverslag-phil-kraft-kwik-fli-mk-iii.html]Babelfish translation of Dutch original[/link]
I have seen that the results are hilarious sometimes...
02-22-2008, 04:08 PM
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RE: Building a Phil Kraft Kwik-Fli Mark III
Hi CaptainV24
Glad to see that you are starting a English Build Thread. I think it could be a real insparation to any new modeler to take the plunge and try building their own plane, either from scratch or a kit. I would like to post a link to this page in the beginners section If it turns out anything like your Dutch page it will be a great learning aid to not just beginners but any modelers.
Richard Browning
Glad to see that you are starting a English Build Thread. I think it could be a real insparation to any new modeler to take the plunge and try building their own plane, either from scratch or a kit. I would like to post a link to this page in the beginners section If it turns out anything like your Dutch page it will be a great learning aid to not just beginners but any modelers.
Richard Browning
02-23-2008, 03:04 PM
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RE: Building a Phil Kraft Kwik-Fli Mark III
(original date: 2007-10-15)
Let's get started:
The wing has a four degree angle. The main spars (left & right) must be glued together in this angle right from the start. We're not building half wings here.
So I drew lines on my building plate using the right angle. Then glued them using epoxy. This needs to be done twice, for both the lower and upper part of the wing. These spars are double with hard balsa spars. I also created a ply rib template.
Let's get started:
The wing has a four degree angle. The main spars (left & right) must be glued together in this angle right from the start. We're not building half wings here.
So I drew lines on my building plate using the right angle. Then glued them using epoxy. This needs to be done twice, for both the lower and upper part of the wing. These spars are double with hard balsa spars. I also created a ply rib template.
02-23-2008, 03:16 PM
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RE: Building a Phil Kraft Kwik-Fli Mark III
(original date: 2007-10-15)
I also started a list for all the things I need to buy:
[ul][*] 1 Steerable nose gear, Robbe 6043 or Kavan 0104[*] 1 Nosewheel (2 1/2")[*] 1 Sullivan pushrod (red) to control nose gear[*] 1 Spinner aluminium (2 1/2"), Great Planes like in drawing[*] 1 Propellor (wood?), brand?[*] 1 Engine mount (or DIY)[*] 1 stuurkabel gas, Sullivan rood[*] 1 Canopy, Sig or Graupner[*] 2 Wheels (3")[*] 2 main landing gear legs, metal rod[*] ? Aileron hinges[*] 2 Ailerons horns[*] ? Elevator hinges [*] ? Elevator horn[*] ? Rudder hinges[*] ? Rudder horn[*] 1 Pushrod rudder, Sullivan blue[*] 1 Pushrod elevator, Sullivan blue[*] 2 Aileron servos[*] 2 pushrods ailerons[*] 2 Elevator, rudder servos[*] 1 Throttle servo[*] 1 fuel tank (300 ml)[*] 1 rx battery[*] 1 receiver[*] 1 rx switch
[/ul]
I also started a list for all the things I need to buy:
[ul][*] 1 Steerable nose gear, Robbe 6043 or Kavan 0104[*] 1 Nosewheel (2 1/2")[*] 1 Sullivan pushrod (red) to control nose gear[*] 1 Spinner aluminium (2 1/2"), Great Planes like in drawing[*] 1 Propellor (wood?), brand?[*] 1 Engine mount (or DIY)[*] 1 stuurkabel gas, Sullivan rood[*] 1 Canopy, Sig or Graupner[*] 2 Wheels (3")[*] 2 main landing gear legs, metal rod[*] ? Aileron hinges[*] 2 Ailerons horns[*] ? Elevator hinges [*] ? Elevator horn[*] ? Rudder hinges[*] ? Rudder horn[*] 1 Pushrod rudder, Sullivan blue[*] 1 Pushrod elevator, Sullivan blue[*] 2 Aileron servos[*] 2 pushrods ailerons[*] 2 Elevator, rudder servos[*] 1 Throttle servo[*] 1 fuel tank (300 ml)[*] 1 rx battery[*] 1 receiver[*] 1 rx switch
[/ul]
02-23-2008, 03:25 PM
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RE: Building a Phil Kraft Kwik-Fli Mark III
(original date: 2007-10-22)
Next steps:
Main spar positioned on the drawing. Used the ply template to create a set of ribs. Put a set of ribs (max 6.) between the two templates and you can easily shape the ribs. I used toothpicks and clamps on the templates to keep them aligned.
I started on the right side of the wing and tried positioning all the ribs. The rear spar is just there to position the ribs vertically.
Then I started gluing in the ribs. The ribs were glued between the bottom and top spar.
These steps go very fast, so I started on the other side.
Next steps:
Main spar positioned on the drawing. Used the ply template to create a set of ribs. Put a set of ribs (max 6.) between the two templates and you can easily shape the ribs. I used toothpicks and clamps on the templates to keep them aligned.
I started on the right side of the wing and tried positioning all the ribs. The rear spar is just there to position the ribs vertically.
Then I started gluing in the ribs. The ribs were glued between the bottom and top spar.
These steps go very fast, so I started on the other side.
02-23-2008, 03:31 PM
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RE: Building a Phil Kraft Kwik-Fli Mark III
(original date: 2007-10-25)
Then I had a question:
The aileron attachment is shown in the image in this post.
I noticed something: no hinges. The drawing show no aileron hinges. What did they use originally, and what would be appropriate now?
I saw some options:
1) Use the cover film as a hinge
2) Use simple plastic flat hinges and mount them as high as possible
3) Use 'pen' (?) hinges
4) Use CA hinges (those flat mylar like things)
I don't like option 1. I'm afraid it will tear eventually or am I wrong?
Options 2 and 3 make it harder to put the hinge point on the right spot.
Option 4 is something I dreaded when building my Sig Kadet.
By the way, I don't want to change the shape of the ailerons. Has to resemble the original...
Then I had a question:
The aileron attachment is shown in the image in this post.
I noticed something: no hinges. The drawing show no aileron hinges. What did they use originally, and what would be appropriate now?
I saw some options:
1) Use the cover film as a hinge
2) Use simple plastic flat hinges and mount them as high as possible
3) Use 'pen' (?) hinges
4) Use CA hinges (those flat mylar like things)
I don't like option 1. I'm afraid it will tear eventually or am I wrong?
Options 2 and 3 make it harder to put the hinge point on the right spot.
Option 4 is something I dreaded when building my Sig Kadet.
By the way, I don't want to change the shape of the ailerons. Has to resemble the original...
02-23-2008, 04:22 PM
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RE: Building a Phil Kraft Kwik-Fli Mark III
(original date: 2007-10-28)
I have finished the spars and ribs part of my wings. Still there is a lot to do:
[ul][*] Landing gear [*] Leading edge[*] Wingtip[*] Balsa covering[*] Cut out ailerons[*] Mount servos
[/ul]
At one point I diverted from the drawing. The rear spars should be doubled with balsa just like the main spars. Then angles used to connect the rear spar are very hard to work out. I just connected the the spars together but skipped the doublers. I replaced the spar doublers with webbing.
The black line in the second picture indicates the place the two rear spars (left & right) have been glued together.
I have finished the spars and ribs part of my wings. Still there is a lot to do:
[ul][*] Landing gear [*] Leading edge[*] Wingtip[*] Balsa covering[*] Cut out ailerons[*] Mount servos
[/ul]
At one point I diverted from the drawing. The rear spars should be doubled with balsa just like the main spars. Then angles used to connect the rear spar are very hard to work out. I just connected the the spars together but skipped the doublers. I replaced the spar doublers with webbing.
The black line in the second picture indicates the place the two rear spars (left & right) have been glued together.
02-24-2008, 05:29 AM
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RE: Building a Phil Kraft Kwik-Fli Mark III
When I started building, I emailed Richard Browning ('tweedy' on this forum) that I am using his CAD plans to build the Kwik-Fli Mk III. He responded enthusiastically and has been helping me since.
He is even known the follow the original thread in Dutch (using Babelfish I guess), because sometimes he responded to question that have only been asked in Dutch.
(original date: 2007-10-28)
Some quotes from the e-mails he sent me:
Of course I've been having problems with availble wood sizes. In our shops all sizes are metric. The original drawing using inches and such.
I also wondered about the kind of propeller they used in 1967.
It is really great to have someone helping you who is one ocean and one continent away! Or just a few milliseconds on the internet...
He is even known the follow the original thread in Dutch (using Babelfish I guess), because sometimes he responded to question that have only been asked in Dutch.
(original date: 2007-10-28)
Some quotes from the e-mails he sent me:
When I drew this set of plans I tried to keep the design as close to the original drawings as published in (Model Airplane News). The main change that I made was to switch from a diamond shaped leading edge to a two piece one, using a sub leading edge. I did this because I find it to be an easier way for me to construct a wing. I left the fuselage formers, firewall and nose ring locations just as Phil Kraft had designed them.
As for the metric spars the front spars are ¼†so 6mm spruce or hard balsa should work fine I used spruce for the front spars and balsa for the rear if you use balsa for the rear spars 3/16X3/8 couldn't’t you just get some sheet stock 4.5mm and use a balsa stripper to strip it to 3/8� I you wanted to use spruce for the rear spars you could get the nearest larger size and using a razor plane it down to the proper size or if you send me the dimensions of the spars you want to use I could redraw the ribs for you to accommodate the metric size spars. Also Phil Kraft used balsa spars on the original.
As for the prop that Phil would have used 90% of the props used in the U.S. at that time were TopFlite maple they TopFlite does not make props anymore but they are on ebay all the time Nylon props were almost never used for competition at that time.
02-24-2008, 07:34 AM
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RE: Building a Phil Kraft Kwik-Fli Mark III
Here's a real good article on hinges. I have always used pinned hinges myself.
http://www.airfieldmodels.com/inform...are/hinges.htm
Very good build thread.
http://www.airfieldmodels.com/inform...are/hinges.htm
Very good build thread.
03-09-2008, 03:47 AM
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RE: Building a Phil Kraft Kwik-Fli Mark III
(original date: 2007-11-09)
The landing gear support has been put in place, including the neccessary reinforcements for the ribs the go through.
The root rib has been cut through in 3 places (phew!). Braces have been glued in to attach all spars together. I have use little triangular pieces of wood as an extra to make it stronger and cover small gaps.
I have started on preparing the balse wing covering.
The landing gear support has been put in place, including the neccessary reinforcements for the ribs the go through.
The root rib has been cut through in 3 places (phew!). Braces have been glued in to attach all spars together. I have use little triangular pieces of wood as an extra to make it stronger and cover small gaps.
I have started on preparing the balse wing covering.
03-09-2008, 03:55 AM
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RE: Building a Phil Kraft Kwik-Fli Mark III
(original date: 2007-11-09)
In the dutch forum two question came up.
First question: Why are these braces so small?
Attached to this message is small piece of the original drawing (thanks to Richard). You see the middle of the wing with the aileron servo. De rootribs are easily recognizable (the are double). The DB1, DB2 and W2 ribs form a box. Contrary to some other wing constructions this wing is not build in two halves and then joined together using braces. It is build as one whole. The spars are connected together as the first build step. The general concensus seemed to be that this is indeed strong enough.
Second question: Are the reinforcements for the landing gear strong enough?
Again my construction is entirely according to the drawings. The wings will be covered with balsa in this area. Again the concensus seemed to be that this is strong enough.
In the dutch forum two question came up.
First question: Why are these braces so small?
Attached to this message is small piece of the original drawing (thanks to Richard). You see the middle of the wing with the aileron servo. De rootribs are easily recognizable (the are double). The DB1, DB2 and W2 ribs form a box. Contrary to some other wing constructions this wing is not build in two halves and then joined together using braces. It is build as one whole. The spars are connected together as the first build step. The general concensus seemed to be that this is indeed strong enough.
Second question: Are the reinforcements for the landing gear strong enough?
Again my construction is entirely according to the drawings. The wings will be covered with balsa in this area. Again the concensus seemed to be that this is strong enough.
03-09-2008, 04:00 AM
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RE: Building a Phil Kraft Kwik-Fli Mark III
(original date: 2007-11-17)
I've been working on covering the wing with balsa sheet. I've finished the front and a little piece of the rear side of the wing.
I'm using a kind of 'iron-on' method. Put glue (wood glue) on the right places on the sheet. Let it dry partially, then use your iron to make the glue soft again and attach it to the wing.
I've been working on covering the wing with balsa sheet. I've finished the front and a little piece of the rear side of the wing.
I'm using a kind of 'iron-on' method. Put glue (wood glue) on the right places on the sheet. Let it dry partially, then use your iron to make the glue soft again and attach it to the wing.
03-09-2008, 04:04 AM
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RE: Building a Phil Kraft Kwik-Fli Mark III
(original date: 2008-01-06)
All right. November and december are behind me. All family birthdays and holidays are behind me. Let's work on the Kwik-Fli again!
The little things I've done are covering the wing and starting to work on the ailerons.
I've marked the bottom side of the aileron with a lot of little holes. Now I know where to cut.
I have created a horn from circuit board material and attached to the aileron.
All right. November and december are behind me. All family birthdays and holidays are behind me. Let's work on the Kwik-Fli again!
The little things I've done are covering the wing and starting to work on the ailerons.
I've marked the bottom side of the aileron with a lot of little holes. Now I know where to cut.
I have created a horn from circuit board material and attached to the aileron.
03-09-2008, 04:07 AM
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RE: Building a Phil Kraft Kwik-Fli Mark III
(original date: 2008-01-06)
Continued covering my wing.
Removed the covering for my landing gear.
Put cap strips on my ribs.
Continued covering my wing.
Removed the covering for my landing gear.
Put cap strips on my ribs.
03-09-2008, 04:10 AM
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RE: Building a Phil Kraft Kwik-Fli Mark III
(original date: 2008-01-13)
Attached and formed my leading edge. My template is next to the wing in the picture.
I have really had it with this wing for now...
Parallel with finishing my wing (ailerons, tips, servo's) I'm going to start om my fuselage. I have started cutting the first formers...
Attached and formed my leading edge. My template is next to the wing in the picture.
I have really had it with this wing for now...
Parallel with finishing my wing (ailerons, tips, servo's) I'm going to start om my fuselage. I have started cutting the first formers...
03-09-2008, 04:13 AM
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RE: Building a Phil Kraft Kwik-Fli Mark III
(original date: 2008-01-21)
As I wrote in my previous post, I needed a little break from working on my wing. So I started something simple: the horizontal stabilizer.
As I wrote in my previous post, I needed a little break from working on my wing. So I started something simple: the horizontal stabilizer.
03-09-2008, 04:28 AM
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RE: Building a Phil Kraft Kwik-Fli Mark III
(original date: 2008-01-21)
The horizontal stabilizer is pretty easy to build, some remarks (for those people in the metric parts of the world):
Using the sizes on the drawing you end up with a 5/16" stabilo, which is approx 7.94mm. I've built it using 5mm spars and 1.5mm sheeting, totalling 8mm. Close enough.
Now the fuselage:
The fuselage is built upside down. I have cut out all formers. The firewall is supposed to be 1/4" (6.35mm) aircraft grade ply. I glued this together using 3 layers of 2mm ply (first picture). The rest is made from 6mm or 5mm balsa.
Two pieces of triangular balsa (should be 1/2", 12,7mm. I could only get 12mm) are placed on the drawing. Then glue all formers to them.
The horizontal stabilizer is pretty easy to build, some remarks (for those people in the metric parts of the world):
Using the sizes on the drawing you end up with a 5/16" stabilo, which is approx 7.94mm. I've built it using 5mm spars and 1.5mm sheeting, totalling 8mm. Close enough.
Now the fuselage:
The fuselage is built upside down. I have cut out all formers. The firewall is supposed to be 1/4" (6.35mm) aircraft grade ply. I glued this together using 3 layers of 2mm ply (first picture). The rest is made from 6mm or 5mm balsa.
Two pieces of triangular balsa (should be 1/2", 12,7mm. I could only get 12mm) are placed on the drawing. Then glue all formers to them.
03-09-2008, 04:32 AM
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RE: Building a Phil Kraft Kwik-Fli Mark III
(original date: 2008-01-21)
At this point Richard Browning posted the following in the original forum:
At this point Richard Browning posted the following in the original forum:
I just wanted to congratulate you on the quality job you are doing constructing the Kwik Fli. This build log should serve as an inspiration to any new modeler thinking about building their first scratch built model. From what I have seen so far it is hard to believe that this is your first scratch built model. I would say that 90% of long time modelers could not do as clean a job as you are doing on your first try.
I wanted to give you some info before you got to far along in the construction of your fuselage. It seems the KwikFli is known to have a week spot just forward of the horizontal stabilizer, in a slight crash the fuselage tends to split right in front of the stab. The fixes are either to add an additional bulkhead just in front of the stab or reinforce the inside of the fuselage just forward of the stab with some fiber cloth or doubler of either thin plywood or some balsa with the grain running vertical or any other way you can think of to add some strength in this spot.
On My plane I used a commercial glass filled nylon engine mount and had to grind parts of it away in order to move the engine aft close to the firewall as it was positioned with the backplate mount used on the original. Although I don’t foresee having any problems with my mount I don’t like the way it looks if I had to do it over I would do it the way that TopFlite Models did on their Kit of the KwikFli III. They simply epoxied Hardwood (Maple) motor mounts on the inside of the fuselage on each side forward of the firewall reinforced with balsa blocks below and above and drilled for the mounting bolts with blind nuts permanently installed using modern slow setting epoxy. This system I think is every bit as strong as any other method and you can slide the engine aft right up to the firewall it is not necessary to extent the mounts aft threw the firewall as was done back in the days before Epoxies were readily available to modelers. You might ask around and see if you can find a modeler with a set of the TopFlite plans and scan the nose section for you
I noticed that in starting construction of your fuselage you have pinned the fuselage formers and triangle stock down to the plans. I’m sure you have a plan as to how you are going to proceed with construction but the typical way that a Kwik Fli Fuselage is to start by laying out the top view of the fuselage on the top block and then pinning and gluing the triangle stock and bulkheads to that, followed by the side etc. I’m sure that what ever other method you use will work fine given you obvious skill just thought I would point that out to you in case you think it might work better for you.
Have you decided weather you are going to use an iron on film to cover your model? Have you considered (silk and dope) or the more modern equivalent (Dacron and Epoxy-Polyurethane)? Given your obvious talent and If your shop has adequate ventilation or the weather permits finishing outdoors I think you could really have quite a plane and there is something about a well done fabric and paint finish that adds a beauty and permanence to a model that is hard to duplicate with an iron on film. Also it adds much strength to a model, in fact many early planes in the same generation as the KwikFli the fabric covering was important to keep the model from experiencing structural failure during high G maneuvers although I have not herd of any problems covering the KwikFli with a Film covering.
Sorry for posting in English but here in the U.S. we are pretty backwards when it comes to learning other languages and if we do it is almost always Spanish.
Congratulations on a great Job can’t wait to read the flight report and hopefully some photos or a video.
Richard Browning
I wanted to give you some info before you got to far along in the construction of your fuselage. It seems the KwikFli is known to have a week spot just forward of the horizontal stabilizer, in a slight crash the fuselage tends to split right in front of the stab. The fixes are either to add an additional bulkhead just in front of the stab or reinforce the inside of the fuselage just forward of the stab with some fiber cloth or doubler of either thin plywood or some balsa with the grain running vertical or any other way you can think of to add some strength in this spot.
On My plane I used a commercial glass filled nylon engine mount and had to grind parts of it away in order to move the engine aft close to the firewall as it was positioned with the backplate mount used on the original. Although I don’t foresee having any problems with my mount I don’t like the way it looks if I had to do it over I would do it the way that TopFlite Models did on their Kit of the KwikFli III. They simply epoxied Hardwood (Maple) motor mounts on the inside of the fuselage on each side forward of the firewall reinforced with balsa blocks below and above and drilled for the mounting bolts with blind nuts permanently installed using modern slow setting epoxy. This system I think is every bit as strong as any other method and you can slide the engine aft right up to the firewall it is not necessary to extent the mounts aft threw the firewall as was done back in the days before Epoxies were readily available to modelers. You might ask around and see if you can find a modeler with a set of the TopFlite plans and scan the nose section for you
I noticed that in starting construction of your fuselage you have pinned the fuselage formers and triangle stock down to the plans. I’m sure you have a plan as to how you are going to proceed with construction but the typical way that a Kwik Fli Fuselage is to start by laying out the top view of the fuselage on the top block and then pinning and gluing the triangle stock and bulkheads to that, followed by the side etc. I’m sure that what ever other method you use will work fine given you obvious skill just thought I would point that out to you in case you think it might work better for you.
Have you decided weather you are going to use an iron on film to cover your model? Have you considered (silk and dope) or the more modern equivalent (Dacron and Epoxy-Polyurethane)? Given your obvious talent and If your shop has adequate ventilation or the weather permits finishing outdoors I think you could really have quite a plane and there is something about a well done fabric and paint finish that adds a beauty and permanence to a model that is hard to duplicate with an iron on film. Also it adds much strength to a model, in fact many early planes in the same generation as the KwikFli the fabric covering was important to keep the model from experiencing structural failure during high G maneuvers although I have not herd of any problems covering the KwikFli with a Film covering.
Sorry for posting in English but here in the U.S. we are pretty backwards when it comes to learning other languages and if we do it is almost always Spanish.
Congratulations on a great Job can’t wait to read the flight report and hopefully some photos or a video.
Richard Browning
03-09-2008, 09:19 AM
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RE: Building a Phil Kraft Kwik-Fli Mark III
Hi Captain
Just came across this delightfull thread on the Kwik-Fly Mark 111. Funnily I purchased a kit in Switzerland on the way back from Brazil in 1974!!!!!!!!!!! I started it when I retired about 10 years ago and almost finished it. Just had the eilerons to hinge!!!!!! and final cover. Now perhaps I will finish it as I read your posts. It was a very good kit and enjoyable but I decided at that time to go electric and so no progress from that time. I am not an expert pilot and normally fly slower planes so the prospect of flying this one sort of delayed me also. I therefore especially look forward to your comments when you get to the flying bit.
Just came across this delightfull thread on the Kwik-Fly Mark 111. Funnily I purchased a kit in Switzerland on the way back from Brazil in 1974!!!!!!!!!!! I started it when I retired about 10 years ago and almost finished it. Just had the eilerons to hinge!!!!!! and final cover. Now perhaps I will finish it as I read your posts. It was a very good kit and enjoyable but I decided at that time to go electric and so no progress from that time. I am not an expert pilot and normally fly slower planes so the prospect of flying this one sort of delayed me also. I therefore especially look forward to your comments when you get to the flying bit.
03-10-2008, 01:50 AM
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RE: Building a Phil Kraft Kwik-Fli Mark III
(original date: 2008-01-21)
Normally the Kwik-Fli uses 3/16" balsa sides. In al [link=http://www.fancyflying.150m.com/qwic_fly_iii_build.htm]build log[/link] of the Home and Hobby Solutions kit version I noticed that the doubled it, with what seems to be thin ply wood.
On the right in [link=http://www.fancyflying.150m.com/fuselage%204.JPG]this picture[/link] you can see the ply doubler. The way the fuselage breaks, this seems to be a better solution than extra formers. Gives strength in the right direction when the tail hits te ground in a landing.
It seems the KwikFli is known to have a week spot just forward of the horizontal stabilizer, in a slight crash the fuselage tends to split right in front of the stab. The fixes are either to add an additional bulkhead just in front of the stab or reinforce the inside of the fuselage just forward of the stab with some fiber cloth or doubler of either thin plywood or some balsa with the grain running vertical or any other way you can think of to add some strength in this spot.
On the right in [link=http://www.fancyflying.150m.com/fuselage%204.JPG]this picture[/link] you can see the ply doubler. The way the fuselage breaks, this seems to be a better solution than extra formers. Gives strength in the right direction when the tail hits te ground in a landing.
03-10-2008, 01:55 AM
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RE: Building a Phil Kraft Kwik-Fli Mark III
(original date: 2008-01-21)
This is indeed something that I thought about for a while. De back of the plane is flat, so it's a seems to be a good idea to put that on your building board. I decided to start with the triangle stock and the formers. This way I'm keeping the drawing in view while building up the fuselage.
The build log I linked to in my previous post showed the same way and I decided to follow that.
I have no idea yet, I'll finish and weigh it first. Will see after that.
I noticed that in starting construction of your fuselage you have pinned the fuselage formers and triangle stock down to the plans. I’m sure you have a plan as to how you are going to proceed with construction but the typical way that a Kwik Fli Fuselage is to start by laying out the top view of the fuselage on the top block and then pinning and gluing the triangle stock and bulkheads to that, followed by the side etc. I’m sure that what ever other method you use will work fine given you obvious skill just thought I would point that out to you in case you think it might work better for you.
The build log I linked to in my previous post showed the same way and I decided to follow that.
Have you decided weather you are going to use an iron on film to cover your model?
03-10-2008, 01:59 AM
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RE: Building a Phil Kraft Kwik-Fli Mark III
ORIGINAL: franciscan
I am not an expert pilot and normally fly slower planes so the prospect of flying this one sort of delayed me also. I therefore especially look forward to your comments when you get to the flying bit.
I am not an expert pilot and normally fly slower planes so the prospect of flying this one sort of delayed me also. I therefore especially look forward to your comments when you get to the flying bit.
I'm not an expert pilot either. Actually, I'm a beginner. This will be my first model after my Sig Kadet LT-40 trainer. It was one of the options recommended to me by my instructor as I asked him for his opinion on a good second airplane I could built myself. I was told it doesn't fly too fast but still is a little more demanding than something like the Calmato Sport or Sig Four Star....
We'll see...
