Hello again, Irkent.
Well, your question turned out to be more challenging than I'd
originally anticipated (you knew that, right, or you wouldn't have
For an engine so widely praised and highly regarded, there is
surprisingly little information available online aside from the
standard "company blurb" on the resellers' sites. Even the
rec.aviation.ultralight group at Google Groups had little to offer
(though if you're not already participating in that group, you may
wish to do so...plenty of kindred spirits there).
This created a challenge, in terms of providing "several" testimonials
and professional reviews. What I've done is to provide you with the
limited degree of information I've been able to obtain directly, and
to point you on your way to independently obtaining more of the same.
In the absence of better online material, I trust that this will be
satisfactory. If any of the following is unclear, by all means use
the "clarification" function to request further detail.
Given the lack of online testimonials, I contacted the North American
distributor of these engines and asked for some. Tom Peghiny of
HPower was most obliging, and furnished me with both technical data,
and the names and e-mail addresses of some individuals who use (or
have used) the engine and would be happy to tell you of their
experience with it. Since the Terms of Service here at Google Answers
prohibit posting contact information (ie, e-mail addresses) for
private individuals, I contacted them directly.
Jim Willess of Northern Virginia Ultralight replied:
"I do engine maint on experimentals and ultralights in the Wash. D C
My experience with the HKS is limited. I have flown the engine on an
X-air ultralight trainer. The previous engine was a Rotax 582. There
is a definite power degradation as one assumes you lose 4 HP. I
found the engine to start easy, run smooth both at idle and high
power. If 60 HP is sufficient for the airframe and type of operation,
I would recommend it for the following reasons.
2. High TBO
3. Mechanical complexity reasonable.
4. Low fuel consumption ( I run a 582 and burn 5 GPH - US )
5. It appears to adapt to various airframes readily HAWK, X-Air,
6. I did recommend to my customer the HKS based on my experience on
7. I believe High Power will provide superior service on this engine
here on the East Coast.
His entry in the USUA's club listings is at the following URL. If you
contact him at the listed telephone number, please do so between 8PM
and 11PM his time.
James Peeler, another ultralight flying instructor, wrote:
"I have been extremely well pleased with the performance, sound, and
frugal fuel economy the HKS. I have put 200 hours on the engine in a
2001 Flightstar II SC, which by the way won Best Type Ultralight
Trainer at Lakeland Sun n Fun 2001. I weigh about 220 pounds and most
of my students weigh as much or more. The engine burns between 2 and
2.5 gallons/hour with these kinds of payloads. In my 22 years of
flying and instructing in ultralights accumulating over 5,200 hours of
flying, this is absolutely the best engine I have ever flown. My
engine maintenance on the HKS so far has been preflights, oil
changes, and air filter cleaning. Would I buy another? YES! With the
new price reduction, it is absolutely the best made better. This
engine is an option on just about any first quality ultralight in the
market. Oh yes, last but not least, HPower with Tom and Spark, is
absolutely the most responsible,dedicated, caring, HONEST,
professional team I have ever had the opportunity to have done
AFI USUA, BGI FAA, NAFI Instructor"
A third user, Dave Faneuf, had these comments:
"I've had my HKS for 2 years and would never consider going back to a
Instant start, or nearly so.
Fuel burn=2.5 to 3 GPH.
4 stroke reliability
Small weight penalty.
Installation and setup is a bit more complex than a 2 stroke.
Overall, I'd say the disadvantages are insignificant. Over time, the
HKS will pay for itself in spark plug, oil, fuel, and TBO savings.
You could contact any of these gentlemen by using HPower as an
I found this thread from August 2000 in one discussion group that was
debating the merits of the HKS vs. a Jabiru with higher rated power,
for use in a trike as a glider tug. To quote one of the participants,
"I'd go with the HKS in a heartbeat for Hangglider Tow with the newest
largest two blade POWERFIN and the 3.5 - 1 [gearing ratio]. It is the
nicest engine I have ever seen. The few minor problems are being or
have been worked out. Only pusher installations as far as I know have
had a slight heating problem due to poor air circulation. They fixed
it from factory to not need as much air."
The link is below; use your the Edit/Find function in your browser to
search for HKS:
Mr. Peghiny would be pleased to furnish you with additional
references. You may reach him through the HPower website, given
below. Additionally, any of the builders listed below should be able
to put you in touch with their own HKS users, or mail you printed
Professional reviews of this engine are, if anything, even scarcer.
Like many small, tightly-knit groups of enthusiasts, the publications
that service this community tend to be heavy on user-submitted
contributions. Therefore, many reviews would simply be more of the
same. Even at that, it proved difficult to find more than a line here
and a line there - nothing that could be construed as a proper review.
As an example, here is this site's initial review of the engine from
its roll-out at Oshkosh '97... "We had reported on the arrival of the
HKS 700 E motor, here on a Flightstar. As flown here, it seems less
noisy than the 582 Rotax, with equal performances."
This page, from the Thompson Valley Sport Aircraft Club in British
Columbia, details a flight made by an instructor through the
mountains, in a Chinook with a brand-new 700e installed. The
powerplant's fuel economy is emphasized:
I also found this review, (Experimenter Magazine, Aug 2000) on the
website of Canadian builder ASAP (see below), which flight-tested an
HKS-equipped Chinook. The article contains much pertinent commentary
on the HKS. An excerpt:
"The HKS seemed hardly to be working to fly me and the Chinook around.
I imagine that it would do nearly as well even loaded with two large
pilots. This impression has been confirmed flying other HKS-powered
ultralights with two on board.
[ASAP owner] Holomis expresses a lot of satisfaction with the engine
distributed by HPower Ltd. and sees a market for the 60-horse,
HKS-powered Chinooks among pilots who prefer the reliability and long
life of four-stroke engines. They'll also like the smooth torque power
through a wide operating range and the very low fuel usage. Many HKS
users report a fuel burn as low as 2.0 gallons an hour, less than a
503 doing the same work and under half that of a Rotax 582."
For the full article, click this link:
At one of the Bede sites, I found this test report on the second
BD-17, which has a few things to say about the engine:
I'm sure there are other such reviews buried on manufacturers' sites,
but I browsed a great many without finding them. You may wish to
contact local chapters of the EAA and USUA in search of paper copies
of the more popular publications.
Beyond this, however, there is one group of technically proficient
experts who do give significant thought to available engines. That
would be the builders and designers of ultralight aircraft. And with
them, as you know, this engine has been a huge success. I have culled
a representative selection of designer/builders' sites for you to
examine. The staff at any of these manufacturers should be able to
furnish you with their reasons for choosing the HKS, and their
experience to date with that powerplant:
Bede Aerosport has been around for a long time, and was a pioneer in
lightweight aviation. Remember the BD-5J, the mini-jet that got so
much attention in the 70's? The HKS 700e is the first powerplant to
be tested and recommended for use in their current BD-17 airframe.
Finnish designer Jukka Tervamaki has been flying ultralights for 27
years, and is the designer of the JT-6 powered glider. As he says on
his site, "While the 2-cycle powerplants are simple I would hardly say
they are reliable. I have never dared to fly long distances with
2-cycle power, the maximum being about 100 km...For years I have been
longing for reliable 4-cycle power..."
For his as-yet unbuilt new design, the JT-8, Tervamaki selected the
HKS 700e for its reliability, fuel efficiency, and quiet operation.
His site is here:
Flightstar, makers of several popular ultralights, have made the HKS
their "official" four-stroke engine (scroll to the bottom):
Canadian builder ASAP, who successfully revived the "Beaver" and
"Chinook" lines from obscurity, made the HKS 700e their four-stroke of
choice as an alternative to the Rotax 503 and 582 two-stroke engines.
Note that this is the only non-Rotax engine in their lineup. See
their FAQ page:
Pegasus Aviation were so delighted with this engine that they created
a flagship version of their popular Quantum series around it, the
Quantum HKS Executive:
For a list of other builders using this engine, scroll down this page
at HPower's website. Many of them have clickable links you can follow
for further information:
And of course, if you've not already done so, you'll want to have a
good look at the rest of HPower's site:
One thing stands out for me, having spent a few days grubbing through
the electronic undergrowth in search of information. I was unable to
find a single negative word about this engine! Normally, as any
retailer will tell you, the people who have the most to say about your
product are the ones who are unhappy with it.
The recurring themes I found, from site to site to site, were
reliability (unusually high TBO), fuel economy, and quiet operation.
These are all excellent things!
I'd mentioned above that Tom at HPower had forwarded some technical
information. You will find it at this link, in MS Word format.
Please note that this file is being hosted temporarily for you on a
private server, and will only be there for a few days, so please
download it at your earliest opportunity.
Oh, yes, and HKS's own website for the engine is here:
I performed several individual searches to find this information.
Typically, I use the general searches to find useful links, and then
follow up by searching on specific brands individually.
+"HKS 700" OR "HKS 700e" +review OR testimonial OR report OR "test
+"ultralight publication" OR "ultralight magazine" +online OR "on
line" OR "on-line"
...and several other variations on this theme that did not yield
Thank you for an interesting inquiry. I had the "flying bug" very
badly as a child, and I think I'm in danger of a relapse, now!