This is far from a current info source on Kolb, but that doesn't keep me
from leaving it up here for posterity. Check the Matronics.com listserve
for more (and certainly more current) information.
-BWR/ 1997
Father's Day
Thermals, Wheelies
Landing Suggestion for First Time
Cruise Speed and Range
Slipping
Spins
Ground Handling ...Uh oh, it's a tail dragger!
Soft Ground Operations
1. Pin the lift strut to the cage.
2. I then swing out the wing from folded position and rest it on my
jacket or a rag to protect the outside corner from the pavement.
- i made some 2"x5" AL plates which i hang on the main cage bulkhead
for the inside wing rib to rest against while the wing is resting
against the cage and the pavement.
3. Pin the spar to the cage. It is helpful to be able to push the plane
backward, holding up the inboard front of the wing until the holes
come into alignment. The outboard end of the wing is still resting
on my jacket and by nudging the plane backward I haven't had to
drag the outboard end of the wing forward for pin alignment.
4. Standing in front of the wing about where the lift strut attaches,
I lift it up, along with the outside end of the lift strut.
(I often hike up the lift strut w/ my foot, just cuz it's easier
to lift the wing w/ both hands.) For clarity to those who haven't
done this, the wing is swinging up from its 2 attach points at the
root -- the U joint and spar_to_cage pin just inserted (in step 3).
Holding the wing w/ one hand, or even resting it on my shoulder, I
place the lift strut into position and rest some of the wing weight
onto it so that it won't move. Then wiggle things slightly and
insert the pin.
Unfolding: How Long???
FireFly
Baggage Space, XC Comfort
My Plane and the other Kolbs:
The Kolb line, more or less
Mine is the model Firestar KXP, which is now replaced by a very
similar derivitive called the Firestar I or II. The I model is
intended to be able to be built under 254 lbs thereby meeting the
FAR 103 UL weight requirement. The II has a jump seat for a
passenger and Kolb also offers a true (side-by-side) two seater
called a Mark III. They also offer a model called the
Firefly, which is also intended to be built to 254 lbs to meet
FAR 103. Kolb is now The New Kolb Company.
Back to Top
Flying Stories:
Windy Day
Date: Sat, 20 Jan 1996
Saturday I dashed out between storms, and it sure was beautiful!
I flew South 40 miles to Lodi and met a friend, then we flew together
up to Jackson in the Sierra foothills. All the big nasty clouds
brewing and snow in the Sierras made for some spectacular scenery.
We then buzzed West, stopped again at Lodi, then across the Sacramento
delta to Rio Vista. Landing there, the windsock was straight out,
with wind about 20 mph. I turned final about a 1/4 mile out at
800 ft AGL, and felt like I was just sitting in the 'down elevator'.
At about 40 mph airspeed, I just watched the runway come up to meet me.
Pretty fun! I took the time for a few strafing runs on a big freighter
chugging up the deep water channel to Sacto, then zipped back North to
Davis (home) as the storm front was closing in from that direction.
It was really gusty, so I made a few extra low and sort of slow
passes down the 4k' runway just to play around with the goofy wind.
I had so much fun, I just can't quit thinking about it! Got the plane
packed, home, and in the garage with only a few sprinkles of rain.
What a blast!
Date: Mon, 17 Jun 1996
I hadn't intended it as a father's day thing, but my parents were coming
to town this weekend and I got my dad up in my plane. Oh what a feeling!
My dad has maybe about 1200 hrs, most of it 40 years ago in B-25s.
He's now current in the low-end Cessnas and flies maybe 2 hours a month.
He also took about 4 hours in USUA training 2 years ago. So anyway,
I figure he's maybe a little rusty in type. I made him stop by on the way
up from So. Cal and get a couple times around the pattern with my old BFI.
Hearing about how that went, I'm glad I did require the familiarization.
He related that the instructor said after the 4th landing ..."well, you
had that one pretty much the whole way in." (gulp)
Getting into my Firestar, my dad did a little bit of taxiing, one higher
speed taxi down the runway, then said he'd go for it. I had given him
all the particulars and suggested his first pass be an approach and 5-10'
agl pass. He couldn't get the darn thing down and passed over at 100'.
He told me later he couldn't see the altimeter either, and that's why he
climbed to what looked like a 1200'agl pattern. He was also "used to"
the Quicksilver w/ 2 aboard, which sinks badly compared to our fine Kolbs.
So, he came back around with a real 5 ft pass, although bobbling a little
w/ over-control. Then he came around again and flared out with 20' of
altitude left in spite of my major emphasis on this -- i didn't crowd
his brain w/ a lot of fluff, honest. I bit my lip and the plane hung
on till about 5-6' and dropped in. The landing gear sucked up the drop
and he went around and did it again. ...ouch, but successful in the
traditional sense (he walked away).
We went home for some mid-day family obligations and returned later to
see if maybe he had thought thru the correct method enf to pull it off
a little nicer. Much to my relief, he had. He went around 4 or 5 times
and made perfect landings each time. Yahoo!
In all, with everything my dad has helped me with and inspired in me, it
was one of the most gratifying moments I've ever experienced.
Date: Fri, 2 Aug 1996
Hi Kolb builders/flyers:
The list is a little sleepy so i thought I'd toss in a little bit of my
doings. A couple weeks ago I went flying for a good part of Saturday
and Sunday. On the way back into my home area I saw a large disked
field with 3 dust devils churning up in the afternoon heat. I'm in
the Sacramento valley, and this afternoon was about 105, which is not
uncommon. Having toyed w/ thermals a little in the past, i headed right
for the biggest of the dust devils. I entered it at 1000'AGL and backed
off to 3400 rpm, and circled at 35-40mph. I stayed here quite awhile,
maybe about 5-8 minutes. Although not spectacular, i continually gained
altitude, and decided i'd had enough at 3000'. Interestingly, I noticed
that there were a lot of swallows that seemed to be riding the thermal
as well.
Another fun thing I did was a variation on an exercise given to me during
my early UL training. That is, to fly the plane at minimum flying speed
right along the runway, usually with wheels skipping about half the time.
The challenge exercises all 4 control inputs: rudder,elevator,aileron,
and throttle. The variation, which was partly just luck, was that I
got the tailwheel to ride smoothly along the strip for several seconds
without the mains touching. This is impossible if it is a little gusty,
because you obviously can't predict the changing wind. But it's possible
in steady air and nets the same satisfaction as doing a tight 360 turn
and hitting your prop wash as you come around. (Be advised i'm not
suggesting anyone do dramatic high incidence angle wheel stands.)
Last weekend i did some maintenance stuff. The main thing i went after
is the where the wing attaches at the rear U-joints to the fuselage.
On pre-flights i had noticed that the castle nuts were not quite tight
enough, allowing the rear of the wing to click up or down -- not much
(1/8"?) -- but enough to seem sloppy. I think paint had worn off the
U-joint since new, creating the looseness. I took the wings and U-joints
off, which was good to do just on general inspection principles. I then
thinned down a new set of washers for the U-joints to a thickness
that allows the U-joint castle nuts to be tightened to the perfect tightness
AND have the cotter pin meet its hole. I also greased areas where the
paint had worn off.
Happy landings everybody.
Flying Technique:
Approach Speed, Landings
Joe, and other soon to be Kolb flyers:
I just read xxxxx's response to Joe's request for some hanger flying
tips, in particular for landing on his "hypothetical" 700 grass strip.
I must say, my methods and opinions differ in almost every way -- except
maybe that part about religion -- from xxxxxx's.
I fly a standard Firestar KXP with 447 and Warp drive prop. I've got
only about 55 hours in it (all since new in March 1995), plus another
5 in UL training, plus another 15 or so in small GA types. Can we
count endless hours of 'yankin and bankin' on an SGI computer flight
simulator? ...those F-16s are tricky you know :)
Because ULs are ULs, they have very little inertia and very light
wing loading. This is obvious, but is key to why ULs land differently
from GA planes. That is, once you flare, you loose airspeed quickly.
Compared to GA planes, I found it a little hard to get used to flaring
so late, but within an hour, this trick was mine. I don't think the
Firestar is more difficult to land than other ULs I've tried. Maybe
a little different, but not difficult. And, I think most would be
surprised that the fact/feature that it is a tail dragger, adds practically
no difficulty compared to tricycles; rather, it just gives you bragging
rights that you drive a taildragger. (A Pitts it is not.)
Here's what I would consider a nominal, 5mph headwind landing:
1. Turn base at about 1/4 mile out, 400 feet AGL, 50-55 mph. Throttle
closed, my policy is to assume it may quit anyway so every landing
is a practiced engine off (or close to it, at idle). At the start of
the downwind to base turn, you should see your touchdown spot 45
degrees behind your wing.
2. Keep 50-55 mph till round-off (aka just before flare). Cheat on whether
you are too high or low by cutting the corner to final, or making it a
real square turn. Again, 50 mph minimum!
3. Add a little slip on final if too long. Verify your engine is still
behaving with bit of throttle, then back to idle.
4. At about 20-25' AGL begin round-off ...slowing down thru 35 mph at
2-3' AGL. Maybe somewhere in here this changes from round-off
to flare. Be careful, if you are not accustomed to flying ULs, you can
go from 35 to under 30 and stall in what feels like 2 seconds. (This
is where ULs can so quickly nail a GA pilot! )
5. Let speed bleed to under 30 and and a stall/3-pt landing (with a
dash of luck). With standard wheels/tires the tailwheel may easily
touch first.
6. For a (fast) wheel landing you should skip the last step, and be
rounding off to 35 mph as the runway comes up to meet you. Start
the round-off (step 4) no higher than 20'.
This is not all that tricky. Almost Vne? C'mon! It gets a little more
involved for cross-winds, but I've practiced these in about 12+ mph full
X-wind. Yes, it does require your attention. I would think X-wind
landings would be much more difficult in something like a Quicksilver
w/ their high dihedral and probably lighter wing loading.
One more thing, Joe. I think you'll find your 700' strip not all that
short, especially since it rises to slow your roll-out. Should be great!
Keeping your speed on final is just a little more important cuz you have
a bigger arc to round-off before touchdown.
More hangar flying comments anyone?
I responded earlier to this thread with a description of my
nominal landing method in my Firestar KXP. Before this subject
fades, I have a couple extra tid-bits to add:
1. Although I said I try to not use any power on the whole approach
so as to be more familiar with an engine-out glide path, I would
suggest that new fliers carry some power all the way to touch
down, or there abouts. Some power (3.5k rpm?) is just enf to
add more controlling air over the tail surfaces, and also
greatly reduces the tendency common to all ULs for it to
slow down faster than expected if you flare to soon.
Also for first flights, I would suggest rehearsing the word
'gradual'. I think gradual throttle and stick changes are
key to getting used to an unfamiliar plane, as the typical
tendency is to over-control.
2. Like Mike, I prefer full stall 3 pt landings for the same
reasons he stated. As well, you don't need nearly as long
a field.
Back to Top
Performance:
Rate/Angle of Climb and Sink
Date: Thu, 14 Nov 1996
Here's some of the brief performance checking i did.
These numbers are all the same flight, and all tests started
within 50-1500' MSL on a 95 degree day, so conditions were pretty
consistent:
1. Full power climb:
IAS (mph) Climb Rate (fpm)
35 1050
40 1100
50 950
2. Idle glide:
IAS (mph) Sink Rate (fpm)
38 500
48 650
Airplane Stats:
Firestar KXP, pretty much standard
447 Single Carb Rotax w/ 2.5 B box
Propellor is 66" Warp "high aspect" pitched to 10.5 degrees (tranlates to
66 x 38.4, which is pretty far into the cruise range).
Load on the plane approx 170 lbs plus normal fuel.
BTW, I've checked my IAS and I know that it is accurate.
From this and a few other separate tests i put my numbers at:
best rate of climb & best glide angle ~40 mph or just over
max angle climb and minimum sink rate ~38 mph
This is really a very limited test and sort of rough. My ability to
lock onto 35 mph, stay exactly at that speed and check my watch (and
chew gum :-)), allows for some error. At 1000 fpm, missing the start
and stop times of a timed one minute climb by a total of 5 seconds would
account for an 83 fpm error (8 %).
>what about cruise speed and range?
i cruise @ 55-57 at ~48-4900rpm, range is 2 hours, plus i carry a 2.5 gal container
giving me another hour but must stop somewhere (anywhere) to transfer
it into the main tank.
On Sun, 11 Feb 1996 Joe.Kohler@top.monad.net wrote:
> Also, how are FS II's coming in CG wise? I had heard that they tended to be
> near the AFT limit.
>
> Another unrelated question: how effectively do Kolbs slip to loose altitude?
> I've heard conflicting things about this.
My Firestar KXP came in near the aft CG limit, but I forget the exact numbers.
That's with me (153), gas (30 lbs), brakes (7.5 lbs), and the fuse tube 3"
shorter than standard.
Slipping. (maybe not such an unrelated topic)
I wouldn't say they don't slip, but it isn't what I was used to in a
Cessna. When i push in the cross controls for a slip the most noticable
and unexpected thing that happens is how much the nose wants to come up.
This can really bug you cuz you are crossed up anyway, and you feel
your speed bleed off quickly. Naturally, I push the nose down to keep
the speed up, and because of the need to do this, I think it is fair to
claim that the slip is increasing my decent rate. In theory it must do
so at least a little, just because of the drag of cross controls.
I get an uncomfortable feeling, however, when if in a full rudder slip
I can run out of down elevator control. I quickly alleviate this by
getting off the rudder. I do slip when too high on approach, but am
careful not get too heavy on the rudder.
After I tried out spins in my Firestar, anybody I mentioned it to said,
"intentionally?!" Well, yes of course! I'm here aren't I? I was chicken
to do much as the Firestar manual says that it develops into a rapid
rotation. So initially I just did spin entries. After 4 or 5 of these
I held the stick back and rudder in just long enf to do a full turn.
I could tell right away that the Firestar does in fact spin rapidly, and
the entry felt rapid and semi-inverted, which is not unusual for some
planes. I had only done spins in one other plane, a TaylorCraft, with an
instructor, and it's spin was much slower in entry and in rotation. It
really felt like no big deal at all. (TCraft have much more fuselage
area to slow down the spin i guess.) Another characteristic about the
Firestar spin is its sudden entry. If you push the rudder at stall,
over you go ...right now! The main thing i learned from trying spins
is not the "training" of recovery technique, but rather that if I ever
unintentionally get into a spin down low, it would be over soon. I am
all that much more reverent toward airspeed in the pattern -- especially
in turns, and stay away from "exciting" maneuvers down low. I'm overdue
to get up there and do some more to (in theory) get "comfortable" with
them. BTW, I did my first spins starting at 4500 AGL, far above what's
necessary, but that's the point. I would advise people to go do some
spins with an instructor before trying them on your own, as you can't
be sure how your brain will react in spite of how much visualization
you've done.
>how are the kolb's ground handling characteristics?
Piece of cake. You'd think you are cheating, it is so easy. I've landed
in upto 12+ mph of 90 degree X-wind on a v. narrow runway. My only
comparison in taildraggers is just a couple hours in a T-Craft. The Kolb's tail
dragger characterstics are much easier to land with less tendency to bounce
a too fast landing, and always full visibility forward.
Date: 18 Aug 1996
Hi Kolb folks, Thought I'd post a little flying news:
A couple weekends ago I flew on up to Colusa, and then about 10 miles
further north and landed along side the Sacramento river. Colusa was
just a gas stop so that I'd have enf to make it home and not risk the
gas guy going to bed too early (old timer, farmer) to top me off for
the ride home. I found a place along the river with about 30' of firm
ground changing to soft sand. Landing was fine, although in taxiing I
had to play enf throttle to keep the tail up off the sand, but not too
much or the nose would go over with the mains unable to keep rolling
thru the soft sand. This happened once, but I had experienced it once
a year ago. (It is only most probable when your speed is down to 0
and you add throttle too quickly.) This time I didn't even get out of
the plane; just stuck my foot out and pushed myself back onto the tail.
While stopped I could see that my tail wheel was buried about 5", and
no surprise, drags a decent groove thru the sand. I know that with me
in the plane, the weight on the tail wheel is 30lbs, and that's a pretty
small footprint back there for even that little weight.
On departure I tested to see if i could get going from stand-still
in the sand. I did, although it was a little tricky, but gratifying.
(If I bogged down, i had a stretch of firm ground to use instead.)
Again, it's a matter of gradually and carefully adding throttle so as to
get the tail flying, at which point you add enf up elevator to keep from
nosing over as the mains push along the sand. It gets easier the faster
you go, and eventually, after a light touch of the mains against the tops
of some sand crests, you're away. I really doubt you could get away with
this without "tundra" tires, even in the lighter single place Kolbs.
(BTW, I walked my intended takeoff zone ahead of time just to get a
sense for it and how much it might be cluttered with unseen tire spikes.)
Anyway, glad to know that i can do that now, as I've envisioned a trip
along the coast and hope to find a spot where i can land on the beach
and get away without trouble ...technical or legal. Moral: Big tires
are a safety feature, as well as a nice ingredient for funner flying
destinations.
Before heading home I also did some low flying thru a field with rainbird
sprinkler irrigation, so that hosed off the bottom of my plane (sort of).
...flew right down the row several times, which is fun and and picturesque
as the spray made a nice rainbow ahead of me. Had a blast.
Trailering:
How do you fold and unfold the wings?
> 3) Can a Kolb be folded/unfolded with only ONE person doing the work?
> Anyone with the detailed knowledge of how to do this, please let me know.
> I'll be very appreciative.
Yes. This is how i do it ALL the time and this is how i PREFER it. By
myself, I move fluidly thru the process and it's easier than directing
"helpers". I'm not sure what to describe, as it seems like there is no
place where you need help. If it is windy, having someone available to
help keep parts from blowing over is required. However, I usually
assemble and disassemble behind some hangars -- a habit formed because
ULs were at first unwelcome at my airport -- and 20 mph winds on the
runway are not a problem to me. I can't see using a tri or bipod; this
is one more piece of junk to haul around, something else to place in
the right position, and probably entails a method more inviting to a
wing blowing away during assembly.
here's some detail...
> The literature says from trailer to fully ready to fly in 8 minutes with no
> tools. Granted, I'm a novice and very inexperienced at this, but that
> length of time seems a wee bit optimistic.
>
8 minutes is do-able, but not practical. You must, in reality, factor in
untying from the trailer, folding out ramps, talking to others, sipping
your coffee, being careful, packing some goodies, and then do a pre-flight.
NO other vendor offers a plane that keeps the airplane assembly phase to 8
minutes, solo! And to boot, it is one of the strongest, best performing
airplanes you can find. For me, honest engine, it is usually 45 minutes
from airport arrival to engine start, and 30 minutes from engine off to
leaving for home.
> 2) Also, (and I just tried this for the first time two days ago), what's the
> trick to fastening the folded wings into the brackets at the bottom of the
yep, brazed welding rod or 1/8" piano wire is what i use and see others
have done as well.
Date: Tue, 16 Apr 1996
> Kolb list:
>
> I read in an article or in the Kolb literature
> that the second strut on the FireFly is to add
> more drag, so the level flight top speed is not
> exceeded on paper. Other "features" such as the
> winshield and really long chord were were
> designed with high drag in mind.
>
> It seems to me that it would be easier to limit
> the level flight top speed with a different prop
> (lower angle) and the RPM limit of the engine.
>
> I do understand that Kolb was trying tho keep
> the full horsepower of the 447, so a real simple
> fix like a smaller carburetor or smaller prop is
> out.
>
> >From my limited experience with soaring, I have
> really come to think of drag as the enemy, and
> have a hard time understanding when someone
> would actually is trying to increase it.
>
> Could someone enlighten me? Would the low pitch
> prop idea work?
Brent,
I believe your suggestion for a flatter pitch prop is good except that
the engine would overspeed. I would guess this could be prevented with
some sort of rpm limiter (electronic ?) add-on to the engine.
Although drag is no friend of most airplanes (perhaps an exception for
aerobatic types), the FAA allows some pretty nice freedoms IF we can
build a plane under 254 lbs and under 63mph. The Firefly design is like
legal tax avoidance -- any legal "paper" allowance
is taken for drag that will de-rate the airplane. The need to use FAR 103
"paper" drag numbers (loopholes?), is partly because, with a short wing
span, the Firefly would have comparatively little drag (as well as less wing
weight). In short, I bet the plane performs
better in the air than it does on paper. The paper version *must* add
up to FAR 103, though, or the whole design concept is lost.
BTW, I don't mean to imply that calculated drag or other performance
parameters are just bunk. I'm suggesting that the FAR nomograms must
have some slop, and that if the design is always on the performance
side of the slop, the plane could be better in real life than an average
nomogram airplane.
Anybody know about electronic rpm limiters? I bet it might be a
relatively simple off-the-shelf adaptation, and -- like Brent said --
a better idea than adding drag (real or paper).
> >Thinking about buying the 2 place version. Tandom or side by side i'm not
> sure.
> IMHO,
> The real question is do you want to tour with someone else, or do you just
> want take someone for a quick ride? The Twinstar is a full two seater - the
> Firestar II is occasional only. FSII is lighter, smaller, ...
>
> >Is there any room for overnight baggage?
> Twinstar yes, otherwise, not really.
>
> >Comfortable for short x-countrys of abt 250 miles?
> No problem, I believe. We went the equivalent of MA to Florida and VV, a
> couple years ago, in a Mark I Twinstar.
My $.02 to add: I think there is room for some overnight baggage in the
FS II. You can't bring everything, but I can cram quite a bit into my
FS KXP and it has less room than the FS I or II. I've brought a sleeping bag
plus 1.5 other sleeping bag stuff sacks full, a tool pouch, all in the
back and still had some room left over. (As well, my BRS is mounted inside
the aft cabin area.) Plus, extra fuel container behind the seat and water
in the front.
Comfortable for 250 X-country? Hmmm: windy and maybe cold or bumpy air
riding a vibrating 2-stroke for 5 hours with 2 fuel stops compared to the
back of a limo, conditioned environment in 4 hours -- No. Fun, interesting,
challenging, great views? You betcha!
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