I own a Beech Sport and I was wondering if there is a STC to change the 0320 150 horse to a 0360 180 horse engine. The Sundowner which is almost the same airframe had the 180 from the Factory. Seems like there would be something out there. I couldn’t find anything when I went to the FAA web site.
Even though the Sundowner had a 180hp engine, there is no STC at this time
to replace the 150hp to 180hp which is a shame. Per the FAA guidelines for a
field approval (8300.10) if you increase the horsepower MORE than 10
percent, it will require an STC. The current mod for our aircraft takes the
power from 150 to 160 which is only a 7 percent increase and falls under the
guidelines of a field approval.
You will find that the 160hp upgrade is great for our aircraft. I have
loaded my Sport 200lbs over gross and at different stations to verify the CG
loading and climb performance and the aircraft performs like a dream with
this additional power. It really makes a difference and is worth the money.
Beech should never had installed the 150hp engine and should have either
stayed with the 165 Continental or the 160 0-320.
As far as the 180hp STC goes, I have been working off and on in that
direction. they 0-360 has different installation considerations then the
0-320 and these differences have to be addressed. The folks at the FAA I
have talked to have said that because the 180hp was installed in the
Musketeer, they would work with me in trying to get an STC going but even
they pointed out that the Modification might be so expensive that it will
most likely be cost prohibitive. Here’s why:
The 0-360 will require a different mount, which may not be too much of a
problem but would have to be addressed anyway for the STC.
You would not want to go through all this trouble and not put on an
overhauled engine. This will be approx $15,000
Guess what, The prop currently on the Sport is only certified to 165hp, So
now you need a new prop for the 180hp which will cost another $3,000 to
$4,500 and may need an S5 spacer to clear the cowling.
Oh and by the way, the new prop will also need an STC because the sport was
never certified with a 76″ prop so add another cost for the STC.
Now you have a 180hp Sport for around an additional $20 to 25,000. Now what?
Well you have the ability to lift over 2400lbs in a 4 place airplane with no
baggage compartment. If you are thinking that you will get additional speed
guess again. I have done Drag Polers on my sport which say that the faster
the airframe goes, the drag REALLY INCREASES. In fact, according to the
Data, to get an additional 12 mph speed, I would have to install a 200hp
engine because the induced drag climbs so fast due to the airframe design.
Ask anyone who owns a Sundowner and see just how fast they really go at
cruise and you will see my point.
The sport is certified to 2150lbs. So to really be able to use all this new
power, you will need to apply for a gross weight increase which will again
require another STC which will most likely be another $2,000 to $4,000 in
So here is what you end up with. A Sundowner with no Baggage compartment for
around $2,000 additional cost of a Sundowner. The moral here is if you want
180hp, BUY A SUNDOWNER and save you all the trouble for less money and time.
You will go about 7 mph faster, lift 2400lbs legally and have a baggage
compartment all for around the same price of all these STC’s.
I love my sport now with the 160hp increase and I know that if I ever need
to load it beyond the 2150lbs, It can handle it and then some. As far as
bags go, the kids are fine with the bags between them. They set their game
boys on the bags like a table and after about an hour they are asleep
I hope this helps.
Southwest Regional Director
Beech Aero Club