🚀 go-pugleaf

In article <1993Jan25.194739.3645@mlb.semi.harris.com>,
mwp@ms9.mis.semi.harris.com (Mark W. Poole) writes:
> It looks my next plane will be a Goldberg Ultimate Biplane,
> and was wondering what engines you might recommend.  The box 
> states:
> 
> 	 ".60-.90 2c or .90-1.20 4c"
> 
> What have you "netters" seen used on this plane and how was
> the performance?  I'd like to go with a 4c but the cost may
> be unreasonable to me.  Would an OS 61 BB be enough power?
> 
> 
> thanks,
> 
> Mark.

Here's my $.02 worth:

From what I've seen of the Goldberg Ultimate, it looks like most of the
'stronger' .61's (Y.S., OS SF, SuperTiger) will fly the airplane, but
if you want PERFORMANCE (i.e., pattern-capable), then a 1.20 4C is a 
must.  I'd go with the Y.S. 120 (the A/R is a brute, but the 'normal'
1.20 is more than enuf for this bird) or with the OS 1.20 Surpass II
with pump.  The major differences between these 2 engines that I have 
observed are:

        Y.S.                                O.S.
    lighter  (?? not sure)             comes with muffler 
    slightly stronger  (*)             may be more available
    expensive exhaust system           cheaper, counting exhaust system
    runs great out of the box          runs equally great after a
                                         protracted break-in period
                                         (like 4-5 gallons of fuel)

I own one of the OS 1.20 pumped motors, several friends own the Y.S.

I drive a 9 lb+ MK Lazer with mine, run a 14.4 X 10.5 APC prop at
9,800 RPM static, and have virtually unlimited vertical.  However,
it's taking a long time to get it "broken in" to where it will idle
reliably.  It IS getting there, however.  Others with the Y.S. are
generally running the same or similar size APC props, perhaps 300 -
500 RPM faster.  But, they spend a lot of money replacing flexible
header pipes and mufflers, where I use the stock, comes-with-the-
motor OS muffler with no problems.

I have seen the GB Ultimate with a strong OS .61 SF RE with a pipe,
that flew well, but ran out of steam real quick on the verticals.  I
have also seen a GB Ultimate with a Y.S. 120 do a knife-edge loop.

+------------------------------+------------------------------------+
|  Tom "Krash" Krueger         |    IBM Adv. Wrkstn. & Sys. Division|
|  AMA 374525                  |    Austin, Texas                   |
|  krueger@austin.ibm.com      |    "Home of the RISC System/6000"  |
+------------------------------+------------------------------------+
-- 
+------------------------------+------------------------------------+
|  Tom "Krash" Krueger         |    IBM Adv. Wrkstn. & Sys. Division|
|  AMA 374525                  |    Austin, Texas                   |
|  krueger@austin.ibm.com      |    "Home of the RISC System/6000"  |