Bridi Big Kaos + OPS Maxi 30?    Gallery
View related threads: (in this forum | in all forums)

Logged in as Guest



Users viewing this topic: none
    Search This Thread  
 
Printable Version



All Forums >> RC Airplanes >> Pattern Universe - RC Pattern Flying >> Classic RC Pattern Flying >> Bridi Big Kaos + OPS Maxi 30?
Page: [1]

Tower Hobbies Get Coupon Codes Brands  
Login
Message << Older Topic   Newer Topic >>
Bridi Big Kaos + OPS Maxi 30? - 4/12/2012 1:13 AM   
Scota4570


 

Posts: 799
Score: 115
Joined: 1/8/2009
Last Login: 5/18/2013
From: Salinas, CA, USA
Status: offline 		I was directed to post this thread over her to see what you pattern guys have to say. I am not a competition flyer .

I am about to start a Bridi Big Kaos kit,
http://www.bridiairplanes.com/hangar/bigchaos.html
They are suggesting 90-180 glow. IMHO they tend to be conservative on engines. The wing area is 1140. The weight is suggested at "11-Lbs w/o the engine.

I have a conversion engine just like the one linked next,
http://tech.flygsw.org/OPS.htm
It weighs about 2000 grams or 4-pounds with the muffler. It produces 4 HP at 8300 rps (18x10 prop at 8300)

I looked up some engine specs:
OS AX120 produces 3.1hp for 870 gm
OS BGX 3500 4.04 hp / 1340 gm
ST G2300 3.7 hp/ 1077
Moki 210 3.3hp/ 1275
Moki G180 3 / 1200
OS 160 3.7 hp / 1200

I want as much power as the airframe can handle. I fly pretty well and almost never crash anything. I also do not want to use an engine that is so heavy as to destroy the handling qualities. I am not interested in glow engines, only gas need apply. From what I am gathering I will be increasing the all up weight by about a pound, all else remaining equal, IF I use my OPS. Wouls that extra pound or two make a real difference in handling qualities. Should I shorten the nose a bit. Forget the whole thing and get an OS-160 or ST G2300??

Anyone have any help they can give me on the suitablility of my OPS engine?

< Message edited by Scota4570 -- 4/12/2012 4:56 AM >

Hide Signatures
       Post #: 1

RE: Bridi Big Kaos + OPS Maxi 30? - 4/12/2012 2:04 AM   
turbo.gst


 

Posts: 731
Score: 115
Joined: 2/22/2005
Last Login: 5/20/2013
From: Midland, TX, USA
Status: offline 		I love my OPS Maxi 30cc, but it is a very heavy engine(56 oz's). It is fairly miserly on fuel and super reliable. It is such a smooth runner and is built to last forever with any care at all. I don't know if that is a good fit for it I would use an OS 160 on the Big Kaos.

Hide Signatures

(in reply to Scota4570)
       Post #: 2

RE: Bridi Big Kaos + OPS Maxi 30? - 4/12/2012 5:22 AM   
doxilia



Posts: 4516
Score: 136
Joined: 4/21/2008
Last Login: 5/21/2013
From: Montreal, QC, CANADA
Status: online 		I'm a little puzzled. You mention that you are not interested in glow engines and that you'd like to use gas instead. But all the engines you listed are glow engines!?

There are a plethora of gas engines in the 26 to 40 cc range that could fly this bird...

You might have to go to town on the airframe and lighten yet strengthen where appropriate. This will give you leeway to use a gas engine with better flight performance. I have not built a Big Kaos but no doubt it is designed in the "classic" fashion. Built like a modern 25% scale model, you can loose a fair bit of weight.

David

Hide Signatures

(in reply to turbo.gst)
       Post #: 3

RE: Bridi Big Kaos + OPS Maxi 30? - 4/13/2012 2:28 AM   
Scota4570


 

Posts: 799
Score: 115
Joined: 1/8/2009
Last Login: 5/18/2013
From: Salinas, CA, USA
Status: offline 		I put them there as refrences for weight and power. It appears that the OS-160 is the baseline engine in this airplane. My engine is about a pound and a half heavier. I may be over analyzed this project. I think it is time to build. If I am not happy with my engine I'll get one that is a little lighter. Probably a ST 2300. It is a little lighter than the OS, half the price and about the same horse power.

Hide Signatures

(in reply to doxilia)
       Post #: 4

RE: Bridi Big Kaos + OPS Maxi 30? - 4/13/2012 4:12 AM   
doxilia



Posts: 4516
Score: 136
Joined: 4/21/2008
Last Login: 5/21/2013
From: Montreal, QC, CANADA
Status: online 		I see...

but still no reference to any gas engines you might consider. You are now talking about OS 1.6's and ST 2300; two more glow engines.

If you build for gas, it's one thing. If you build for glow, like the model was likely "engineered", its another. The gas engines are significantly heavier as you mention.

I'd build it for gas and then, if you decide to use glow, more power to you..., literally!

I hear the ZDZ 40 is a good engine for 2x2 size pattern models (the Big Kaos fitting the bill). Alternatively, OS now has a nice gas 33 with excellent performance, good reviews and lightish weight. Photo and manual below. Nice engine!

David

Attachments
Click to see fullsize image.
Click for fullsize 		Click to see the file in new window.Attachment.pdf


Hide Signatures

(in reply to Scota4570)
       Post #: 5

RE: Bridi Big Kaos + OPS Maxi 30? - 4/14/2012 4:16 AM   
speedracerntrixie


 

Posts: 2379
Score: 189
Joined: 6/7/2010
Last Login: 5/21/2013
From: San Jose, CA, USA
Status: offline 		The OPS is one of the engines on my bucket list. I love to tinker and think outside the box so I think the OPS converted to ignition is a great idea. Yes it is heavier but on an airplane that large, pulling a pound out of it as you build it sould be fairly easy. The uber cool aspect of that is you will be flying an upsized classic with a period correct engine. How awesome is that?


Hide Signatures

(in reply to doxilia)
       Post #: 6

RE: Bridi Big Kaos + OPS Maxi 30? - 4/14/2012 5:02 AM   
Scota4570


 

Posts: 799
Score: 115
Joined: 1/8/2009
Last Login: 5/18/2013
From: Salinas, CA, USA
Status: offline 		They seem to be on E-bay regurarly. Bid on them.

Mine was glued with dreid castor. The ring was stuck. I replaced it with with a Frank Bowman ring. The bearings seemed OK at first but needed replacement. The carb was glued and dried up. I bolted on a Walbro. The compression ratio is said to be over 10:1 in the article I linked. The head us actually a washer like affair that fits under the part with the fins on it. I made a new one that uses a CM-6 sparkplug. I made an adjustable sensor bracket. I have been running BECs off my main battery for ignition so I save a little weight there. As it broke in it became easier to start and more powerfull. When compared to other 30cc it is right up there in the horse power department.

Hide Signatures

(in reply to speedracerntrixie)
       Post #: 7

RE: Bridi Big Kaos + OPS Maxi 30? - 4/14/2012 12:44 PM   
jetmech43


 

Posts: 1362
Score: 100
Joined: 10/7/2003
Last Login: 5/21/2013
From: Bartlett, TN, USA
Status: offline 		use the OS 160 tons of power

_____________________________

smooth pass

Hide Signatures

(in reply to Scota4570)
       Post #: 8

RE: Bridi Big Kaos + OPS Maxi 30? - 4/14/2012 11:46 PM   
speedracerntrixie


 

Posts: 2379
Score: 189
Joined: 6/7/2010
Last Login: 5/21/2013
From: San Jose, CA, USA
Status: offline 		Last time I had a project that could have used the big OPS, I did. Lost it in the last few seconds. The airplane ended up getting E power and was flown today. The only airplane in the shop that is in need of engine is a 60" Bucker Jungmeister vintage kit from 1974. I'm thinking Webra 91 on that one.


Hide Signatures

(in reply to Scota4570)
       Post #: 9

RE: Bridi Big Kaos + OPS Maxi 30? - 4/16/2012 12:20 AM   
madcappilot


 

Posts: 8
Score: 100
Joined: 9/2/2006
Last Login: 5/19/2013
From: simi valley, CA, USA
Status: offline 		Being a Kaos fan Im happy to see this post.A friend in our club had bought one and built it.He had changed a few things along the way to update it as far as servo install and gas engine powered.If built to the plan as he had the plane came out tailheavy(over2lbs worth).What he did was installed the servos to the rear of the fuse for both elevatos halves and for the rudder.The engine he chose was the SLE26 and had 4 inch standoffs on the engine so as to clear the rear carb.The plane was designed to have the servos mounted in fuse below the wing trailing edge and a supertigre 2300 in the nose.The plane came out so nice that I would like to do the same and build one as well.With a few changes mainly extend the nose section between 4-6 inches and use A 30cc plus engine instead for more power.The Sle30 is still very light but has more power.The plane flys like the 60 size on a k&b 61 but I think with the 30cc it would be more like the 60 size on a os 61 fsr.He covered the wing and tail in monokote.The fuse was fiberglassed and painted.The current weight is12lbs 6ozs.Thats without the balance weight.He has moved the engine 3 inches forward and still had to add 6 oz to balance for a total of 12lbs 12ozs.I would go with the gas engine as well and moving the servos to the rear.If the engine you going to use is under three pounds I would consider lenghten the fuse 4-6 in.It also makes look a little better as well.(Personal opinion)I would like to hear your progress on the model.Sounds like a neat plane to work on and build. MCP

Hide Signatures

(in reply to speedracerntrixie)
       Post #: 10

RE: Bridi Big Kaos + OPS Maxi 30? - 4/16/2012 2:37 AM   
Scota4570


 

Posts: 799
Score: 115
Joined: 1/8/2009
Last Login: 5/18/2013
From: Salinas, CA, USA
Status: offline
quote:

ORIGINAL: madcappilot

Being a Kaos fan Im happy to see this post.A friend in our club had bought one and built it.He had changed a few things along the way to update it as far as servo install and gas engine powered.If built to the plan as he had the plane came out tailheavy(over2lbs worth).What he did was installed the servos to the rear of the fuse for both elevatos halves and for the rudder.The engine he chose was the SLE26 and had 4 inch standoffs on the engine so as to clear the rear carb.The plane was designed to have the servos mounted in fuse below the wing trailing edge and a supertigre 2300 in the nose.The plane came out so nice that I would like to do the same and build one as well.With a few changes mainly extend the nose section between 4-6 inches and use A 30cc plus engine instead for more power.The Sle30 is still very light but has more power.The plane flys like the 60 size on a k&b 61 but I think with the 30cc it would be more like the 60 size on a os 61 fsr.He covered the wing and tail in monokote.The fuse was fiberglassed and painted.The current weight is12lbs 6ozs.Thats without the balance weight.He has moved the engine 3 inches forward and still had to add 6 oz to balance for a total of 12lbs 12ozs.I would go with the gas engine as well and moving the servos to the rear.If the engine you going to use is under three pounds I would consider lenghten the fuse 4-6 in.It also makes look a little better as well.(Personal opinion)I would like to hear your progress on the model.Sounds like a neat plane to work on and build. MCP


Glad I read this, it make me more secure in what I already did. I consitered circumsizing the nose. I looked at is an thought if looked pretty short already so, I didn't.

Your buddy had to add 2# (900gm) to the nose with his "SLE 26" engine. I could not find a "SLE" But, most 26's are running about 1000 grams. My engine is about 1900 grams. That comes out about perfect. The fuselage section in front of the wing is very short. The OPS engine fits the length really close to the plans. If the balance comes out right the OPS will work out good. It has more power than the OS 160 that is suggested as the baseline engine. Apparently the OS 160 would require lead in the nose??

I framed up the tail feathers and got the fusalage about 90% there in about 10 hours this weekend. These OLD kits go slow and require a lot of head scratching. I like the process though.

I may do the cowl differently than the plans. I have had good luck with putting fiber glass over green florist's foam plugs.

< Message edited by Scota4570 -- 4/16/2012 5:35 AM >

Hide Signatures

(in reply to madcappilot)
       Post #: 11

Page:   [1]
All Forums >> RC Airplanes >> Pattern Universe - RC Pattern Flying >> Classic RC Pattern Flying >> Bridi Big Kaos + OPS Maxi 30?
Page: [1]





Jump to:


 
Google 



Search | Marketplace | Event Calendar | Local Clubs | Magazine | Product Ratings | New Products | Discussion Forums

Photo Gallery | Instructor Search | Field|Track|Marina Search

Advertisers | Hobby Vendor Resources | Rate Manufacturers | Sign In/Sign Up

SITE MAP!   : :   FORUM RULES

RC Universe is a service of Internet Brands, Inc. Copyright © 2001-2013.

Charities we support that also need your help
Yorkie Rescue | Humane Society | ASPCA | Crohn's-Colitis America


0.816RCU1