New Products Flash Sale
Thread Tools
Old Apr 07, 2015, 01:32 PM
Fluxone is offline
Find More Posts by Fluxone
Registered User
Joined Apr 2015
11 Posts
Build Log
Guillows Kit 305 DHC-2: FF and RC build

Guillows Kit 305 DHC-2

CX-BVR: FF and RC build

This is my first ever rc plane, tissue and balsa build and electric flight conversion. Ambitious? Maybe. Naοve? Hardly, with so much information available now it almost takes the fun out of the challenge. Almost :-)

Having read so many conversion threads dating back to the turn of the 21 century it seems a lot has progressed in the rc aircraft world and a new era of innovation is fully realized. From the chilling reality of military UAVs to Amazon drone deliveries we are in an airspace revolution and I am interested. Indeed I have always been interested in flight – simply it is exceptionally awesome. I am an architect and mechanically minded, I like building and industrial design – now where to start? Something that exudes the simplicity of flight, is renowned by pilots for reliability and ease of flight and is timeless in its design. Having been introduced with near perfection for its intended use – the DHC-2 Beaver will be my first model aircraft to begin my aviation experiments – hence CX-BVR.

I have the privilege of living in British Columbia and have flown in DHC-2 in their native environment a few times. Notably with Nootka Air on Vancouver Island where I was introduced to the simplicity and flexibility of these marvelous aircraft. A few friends and I had planned a surf trip in a remote area accessible only by float plane or boat. At the dock with the pilot we proceeded to remove all the passenger seats to accommodate our gear – provisions, camping gear, surfboards and… an inflatable zodiac, gas and outboard engine! Deflated of course. All our gear was packed into the fuselage – the rear passengers buckled to the top of their duffle bags ready for take-off. This was more like a boat than a plane to me – a simple stripped down tool, easy to fly and easy to maintain in the field. Indeed mostly unchanged since it was built nearly 60 years ago – this plane was a 1950s manufactured DHC-2.

The most complex item in the entire aircraft is the engine – the radial (ed) WASP Jr – what an awesome sound during take-off. In the air, it is just like a boat – you feel the flight and the weather, there is a sense of flight unlike larger faster planes. The DHC-2 wants to fly and is easily controlled by a few cables and a throttle. A few twists of the elevator trim tabs and we are adjusted for our load – everything is simple. Lower the airspeed, drop the flaps and we land in less than 36 inches of water inside a protected reef – hop out and pull the aircraft to the beach – this is as close to a freedom machine as I can imagine. I was in love!

I saw that few people have done the Guillows DHC-2 conversion and have seen it in FF with the requisite floats – very cool! The 24” wing span is a nice manageable size and I have always liked the look of rib and stringer kits so I started the build. I like the fact that these kits can be built as complex or as simple as the modeler would like – they seem perfect for the new era of lightweight electronics. I wonder if Paul Guillow ever imagined that these airframes would be built and flown so well as powered models?

My challenge is thus – to start the model as a scale FF aircraft. I will model all the required modifications for a 3 channel rc model but fly the maiden under rubber power for my own education and model tuning. After a few FF trials I will refit with her RC electronics and an outrunner electric motor. This should be interesting as most people seem to just go for either a low weight FF or a full out RC build.

I have completed the airframe and have scratch built some floats based on the included plans – of course I had to modify them for better scale accuracy. For my satisfaction the floats must be removable to add wheels for land or water take-offs. I am using wheels and landing gear from a micro scale Sport Cub – my included kit wheels were malformed and the Sport Cub landing gear fits the model perfectly so why not?

As I neared completion I realized that I didn’t want to destroy this beautiful model on my first attempt at powered flight. I am confident the aircraft can fly itself during the FF trials but am not confident once I am introduced as the pilot that I will be able to do the same. So, to the relief of many readers I am sure – I have gone down to my LHS and purchased a micro scale Sport Cub with the SAFE feature to train on. I will not attempt to fly CX-BVR under power until I am proficient at take-offs and landings with the SAFE disabled on my trainer. All readers exhale.

Design Targets

Free Flight - Stock Guillows Prop and rubber
Ready To Fly – sub 3oz

Powered Flight - 3 Channel RC (Throttle, Rudder, Elevator)
E-Flight Outrunner 180 power
All Up Weight – 4oz
Ready To Fly – sub 5oz

I will post images and my build specs in my next post. But right now I have a few questions for the community.

1. I was planning on using the increased scale horizontal stabilizer. The Guillow plans indicate this is the preferred empennage assembly for FF. Should I use this stabilizer for both FF and powered flight or should I use the scale sized elevator for powered flight. What would be the flight characteristics with the oversized stabilizer?

2. The Guillow plans suggest a 4 degree dihedral for FF. Should I stick with the 4 degree as I will only have rudder input under powered flight to initiate turns or should I attempt to reduce or increase the dihedral. My understanding is large dihedral angles offer stability and also with a greater dihedral angle I will be able to initiate a tighter turn under 3 channel control – would I be able to initiate an equally tight turn with less dihedral but simply more rudder elevator input?
Fluxone is offline Find More Posts by Fluxone
Last edited by Fluxone; Apr 09, 2015 at 05:17 PM.
Reply With Quote
Sign up now
to remove ads between posts
Old Apr 07, 2015, 02:24 PM
coriolan is offline
Find More Posts by coriolan
"Unnecessary Necessity"
coriolan's Avatar
Canada
Joined Sep 2006
6,374 Posts
Don't bother with the rubber power version, most Guillow scale kits are poor flyers on rubber(more like a powered short glide). Go straight to electric which has been done successfully, it pay to build as light as possible specially behind the CG and not go overboard with scale details in such a small model.
http://www.rcgroups.com/forums/showt...4#post23414260
PS- the Beaver engine is radial but not rotary!
coriolan is offline Find More Posts by coriolan
Reply With Quote
Old Apr 08, 2015, 03:01 AM
Fluxone is offline
Find More Posts by Fluxone
Registered User
Joined Apr 2015
11 Posts
Answer 1.

http://freeflight.org/DigestOnline/T...eStability.pdf
Fluxone is offline Find More Posts by Fluxone
Reply With Quote
Old Apr 08, 2015, 10:44 AM
Fluxone is offline
Find More Posts by Fluxone
Registered User
Joined Apr 2015
11 Posts
Answer 2.

http://www.mnbigbirds.com/images/PDF...hedral_Art.pdf

I like the vector diagrams in these explanations.

http://www.b2streamlines.com/EffectiveDihedral.pdf
http://paperaeroplanes.com/blog/?p=13
Fluxone is offline Find More Posts by Fluxone
Last edited by Fluxone; Apr 08, 2015 at 11:39 AM.
Reply With Quote
Old Apr 08, 2015, 10:53 AM
Fluxone is offline
Find More Posts by Fluxone
Registered User
Joined Apr 2015
11 Posts
I will build and try both stabilizers for fun. I am curious to see the difference in maneuverability between the enlarged and scale surfaces.

As I have only built rudder and elevator controls I will stay with the recommended 4 deg dihedral.

Coriolan, I have already committed to trying the rubber power. If it only glides a bit - so be it - nothing lost. I think I have built it pretty light for FF, the airframe is weighing in at 45grams before tissue so I think I can get the FF RTF in at just a hair over 2oz.
Fluxone is offline Find More Posts by Fluxone
Reply With Quote
Old Apr 09, 2015, 09:19 AM
tarcher3d is offline
Find More Posts by tarcher3d
Registered User
Canada, ON, Port Perry
Joined Mar 2015
1 Posts
I am also building this plane. Will be great to see how they work out :-)



Scrat
tarcher3d is offline Find More Posts by tarcher3d
Reply With Quote
Old Apr 09, 2015, 10:53 PM
Fluxone is offline
Find More Posts by Fluxone
Registered User
Joined Apr 2015
11 Posts
Well - some valuable lessons were learned today. These ultra micro sizes fly really well and the SAFE systems dont really need a pilot to keep a small plane flying. And most important - dont fly a small plane in even a light breeze if you arent experienced - whoops - bye-bye Super Cub. I had a flyaway and lost my trainer.

In a way, that is what is was for so I dont destroy or lose these models while learning the ropes. I wish I had it for longer than a month though :-(

Had I switched off the learner function I probably would have gotten away with just a crash - in my panic I tried to bring her home but the breeze and stability aids had a different destination in mind - I wonder where it went as it beautifully soared away higher and higher and further and further?

Anyway - back to the bench. Just a few more balsa touch ups before I tissue. Some pics attached for your interest.
Fluxone is offline Find More Posts by Fluxone
Reply With Quote
Old Apr 09, 2015, 11:01 PM
Fluxone is offline
Find More Posts by Fluxone
Registered User
Joined Apr 2015
11 Posts
colour scheme... yeah I know the trim tabs are not correct.
Fluxone is offline Find More Posts by Fluxone
Reply With Quote
Old Apr 09, 2015, 11:15 PM
AntiArf is offline
Find More Posts by AntiArf
Registered User
Joined Feb 2013
843 Posts
Some day I'll fly this model again, with the rudder now mixed. The model flew off fine, but had a turning issue with small ailerons, and was getting far away. The floats required reattaching afterward. The model should fly fine with ample dihedral and rudder control.
The one good thing about constructing your own floats, is that you used your own wood. Even with their LC wood, it's not difficult to find better stock. I built them from 1/32" hand cut frames, weighing 10gms each, 1/32" sheeted and iron-on covered. That was heavy enough as it was, let alone using their heavier 1/16" wood.
AntiArf is offline Find More Posts by AntiArf
Reply With Quote
Old Apr 10, 2015, 12:07 AM
Fluxone is offline
Find More Posts by Fluxone
Registered User
Joined Apr 2015
11 Posts
Antiarf, classy three blade prop!

My floats are weighing in at 8 gr total I was amazed at how light they are - I used 1/16" balsa sheet - agreed you can build custom way lighter than these kits allow for - though nothing beats the satisfaction of how fast the cut parts go together.

Are you ailerons on dual servos?

Thanks for the support on my dihedral/rudder comment.
Fluxone is offline Find More Posts by Fluxone
Reply With Quote
Old Apr 14, 2015, 03:41 PM
AntiArf is offline
Find More Posts by AntiArf
Registered User
Joined Feb 2013
843 Posts
Quote:
Originally Posted by Fluxone View Post
Antiarf, classy three blade prop!

My floats are weighing in at 8 gr total I was amazed at how light they are - I used 1/16" balsa sheet - agreed you can build custom way lighter than these kits allow for - though nothing beats the satisfaction of how fast the cut parts go together.

Are you ailerons on dual servos?

Thanks for the support on my dihedral/rudder comment.
Thanks. The ailerons have micro linear servos, although I'm not the biggest fan of them in terms of reliability. They're easy to install, but I actually had to replace one of them during testing. It's a bit of effort, but my favorite method is a single 2.5gm servo with .015" music wire "cable" system, pre-bent to remove friction and with minimal sleeving, routed through the wing formers. Used it on the little Guillows Curtiss Robin. The servo and E-Z link adjuster is at the cabin top, adjusted before covering that area of the cabin.
AntiArf is offline Find More Posts by AntiArf
Reply With Quote


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Build Log Scale Build-Off 4 – Guillows 24" Span Curtiss Robin #305 (discontinued kit) coulee Scale Kit/Scratch Built 85 Yesterday 07:45 PM
Discussion Guillows Kit #902 O-1E Bird Dog Build / RC Conversion coulee Scale Kit/Scratch Built 28 Apr 22, 2015 02:55 PM
Build Log BBCC6 - Kit Build Midway Models "Miss America" FF to RC PGregory Balsa Builders 1 Feb 25, 2015 07:48 AM
Build Log Guillows DHC-2 Beaver Kit# 305 LC RC Conversion Miliroxx28 Scale Kit/Scratch Built 55 Feb 18, 2015 08:21 PM
For Sale Depron kit DeHavilland DHC-2 Beaver made in italy rc plane Robert Boudreau Aircraft - Fuel - Airplanes (FS/W) 0 Jan 05, 2015 01:24 PM