Cessna 170 Laser Cut Kit Build ( # 302 LC )

[SpiceMan]

I've not built this particular kit but, similar ones. Gauging from the wingspan and weight:That model should glide about 25' to 30' feet when gently hand launched.

I wouldn't put any winds on the rubber for the first few trim flights. Without power it should glide straight ahead, with no rolling off to one side.

Did you put dihedral into the wings? I see from your balance rigging photos it appears that you did. Many of these kits have scale dihedral and then a more pronounced flying dihedral.

Wildpig ... Thanks for you're inputs here.

As for dihedral ... you're right, this kit includes two recommended dihedrals. One would be for a "display" build, and the other for the "flying" build. It's determined by the length of the wing struts in the plan. I did the "flying" build version, resulting in a bit more dihedral.

[SpiceMan]

Hi Spiceman,

That is a really neat Jig! I understand it now - thanks for showing it. Yes it sounds like you might some right thrust although 150 turns isn't much, and the torque effect of that tiny prop will be relatively (compared to the span of the model) small. Having said that the Guillows rubber goes very "tight" with very few turns, it is not very stretchy, this may lead to the power burst and torque effect that you observed. To be honest I open the box and the rubber is the first thing I throw away!

The other problem with the Guillows kits are the plastic nose cones, they look good (scale) when compared to perhaps a sheeted nose but there is little chance of getting and accurate and repeatable thrust settings you can be it's a bit fiddly, there are a few threads by people like scigs30 and kittyfritters that show ways to overcome this.

Over on Widdogs Skyraider thread he lists a supplier over in the US for better props and rubber (super-sport). It might be worthwhile getting that sorted before proceeding....

Andrew

Phugoid ... Thank you also for your inputs.
Well, if I get to the "more serious" point on my rubber powered builds, I'll be sure to look into getting better props & rubber. At this point, I'm not intending to enter any contests, so short flights across the park will work for me. Nice that you mentioned the "upgrade" stuff though. That's good info to know.

[SpiceMan]

With the help of my wonderfull daughter, I'm finally able to post my little Guillow's adventure onto YouTube. For any of you that might be interested, here's what I've put together. I'm thinking that there may be some follow-ons, showing better flights for this little gal.
Time will tell.

Cessna 170 Rubber Powered Airplane Pre Maiden Intro
http://www.youtube.com/watch?v=9jJ38PqAquo

Cessna 170 Rubber Powered Airplane Maiden Flight
http://www.youtube.com/watch?v=Y6CrT1QQqUI

Cessna 170 Rubber Powered Airplane Build Slide Show
http://www.youtube.com/watch?v=grs4xLXMK90

[Mitch]

Spiceman,

I enjoyed your video, but my heart was in my throat when you threw that beauty in the air. Before you change any ballast I would try some test glides.

You can leave the rubber in, take off the prop. You do NOT want the "dead" prop acting as an air brake. Put a few winds on the rubber to keep it centered, and you can keep it in place with a dowel or piece of bamboo.

You want to toss it straight ahead, DO NOT throw it up skyward. Let the wings do the work. You want to study the test glide and trim for a straight flight. She should feather out and glide in.

Once you have that you can put the prop on and start winding. You will want down and to the right thrust. You need to know the breaking point of the rubber. What size and how much rubber and how many loops do you have?

She is a real beauty and she would look wonderful in the air!

Mitch

[WIDDOG]

Hi Spiceman.

I totally agree with Mitch especially about your launch technique.

One of my favorite pictures, from the Guillow's site, is Test Pilot Al Smith. Anyway good launch technique is very important.

I recommend you re read pages 23 and 24 How To Build and Fly A Balsa Model Airplane. (little gray booklet)

BTW great looking model.

[Mitch]

Hey Spice et al,

I looked over your post and I like your clean and straight build. I see you come from the RC world. I also see you are using ALL Guillow components, and built as per plans. This is not bad, but you will eventually want better rubber and prop. BUT I have built and flown Guillow models with ALL Guillow parts and it is possible to get a moderate flight.

I see there were ways you could have saved weight in the build, since you are building for Rubber FF. I believe it is REQUIRED when building Guillow kits to be aware that they are OVER ENGINEERED, and you can remove some wood in the build.

You will still want to lube your rubber. Moreover do NOT expect to get more than a dozen flights from that rubber. I competition, flyers dispose of a rubber motor after THREE FLIGHTS!

I think your model looks very nice and congratulate you on you endeavor so far.

Mitch

PS: How come you live in Phoenix and the grass is green and I live in Seattle and the grass is brown?

[Phugoid]

BUT I have built and flown Guillow models with ALL Guillow parts and it is possible to get a moderate flight.

I challenge anyone to get more than a few seconds out of one of these 300 kits with the 5" prop and rubber in the kit. A 5" prop is ok on a dime or a peanut but no use at all on a model of this size, why Guillows persist on still putting it in these kits I'll never know. The only ones in this series with decent props is the beaver and porter, both of which were designed by kittyfritters and have both a little 4" prop for the static builders and a decent 7" prop for rubber power....

I'm more than happy to be proved wrong of course!

Andrew

[Mitch]

To All,

The models I have flown are the 400 series with ALL Guillow's parts. I told Spieman he may want to change the prop and rubber. I have not built or flown this model. I now use the 40 percent rule. My props are approximately 40% of the wingspan. I use a 9-1/2 inch prop on my 400 series, they have a ws of 25-28 inches. Before I was made aware of these things I flew my 400 series with the 7 inch Guillow's prop and Guillow's grey rubber. My best flights were with my P-51 "Miss B. Haven". I am now also using 6 stands (3 loops) of tan rubber 2 x hook to peg length, braided, with a crocket hook. I plan to increase to 4 loops and try that. I may also increase the length of the rubber.

Mitch... Keep Building, Keep Learning, Keep Flying, and most of all Keep Having FUN!

[Phugoid]

40% of 24" is roughly 9 1/2" - getting on for twice the size of the prop in this kit.....

Mitch, sorry my comment wasn't meant to challenge your view per se , but I've seen your builds and not seen one from this series where there is he biggest "prop to span" discrepancy. You can of course get away with smaller props and get reasonable flights but not to this extreme.

I tend to fly indoors and as such I use relatively small props so the model can ROG, duration is not an issue since the marking is purely for flight realism, and they are built very light as they do not have to put up with the rough and tumble of outdoors, so i can use very thin motors, but even so the prop size doesn't drop much below 25% of span.

This is a 21" span model with a 6" prop trimmed to 5 3/4" it weighs just over 30g and the motor is 3.8mm wide tan rubber twice prop hook to peg length, if it weren't so light it would need a much bigger prop and motor.

http://youtu.be/aa3-CVF89Ks

Small props are also easier to trim due to the lower torque reaction, So all in all a 7" prop for a 24" model outdoors would be a suitable one to get a reasonable duration whilst being relatively easy to trim.

Andrew

[Mitch]

To All,

No offence taken, just wanted to clarify... I was trying being trying to be "kind" to say "moderate" flights are possible... That last youtube of ROG was a GREAT flight!
I also did not do my homework and did not know the ws or prop size. I would suggest at least an 8 inch prop. One can also use a 9-1/2 inch prop and trim it down. Then the pitch would be different.
Maybe Spiceman can get some more glide tests and trim flights with what he has... We all have to learn at our own pace, and we all may have different expectations.

I am here to learn as much as to share! Mitch

[SpiceMan]

This is a 21" span model with a 6" prop trimmed to 5 3/4" it weighs just over 30g and the motor is 3.8mm wide tan rubber twice prop hook to peg length, if it weren't so light it would need a much bigger prop and motor.

http://youtu.be/aa3-CVF89Ks

Small props are also easier to trim due to the lower torque reaction, So all in all a 7" prop for a 24" model outdoors would be a suitable one to get a reasonable duration whilst being relatively easy to trim.

Andrew

Hi Phugoid ... Are you sure you didn't sneak some tiny RC gear inside your little bird, for that precise turn / climb / decent, and landing. Someone on the side-line controlling it What a NICE flight