Stevens Aero Model reVerb HLG User manual

Trim Guide
reVerb HLG
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© 2010 Stevens AeroModel. All Rights Reserved.

Balance Model
Proper balance is critical to the performance of all aircraft - no amount of adjustment will correct
the flying characteristics of an improperly balanced model. Check your plans for the location of
the balance point, or Center of Gravity (CG). This will usually be located between 25% and 50%
of the wing chord measured back from the Leading Edge. Balance the glider on your thumb and
forefinger of one hand, directly under the CG point indicated on the plan. the fuselage should
hang level with the horizon. If it doesn’t, add small amounts of clay to the nose or tail of your
glider until it balances level. This is the starting point for balancing your model - you may have to
“fine tune” the CG during fight trimming later on.
Initial Trimming
With the model balanced as above you’ll need to establish a smooth glide with the right amount of
turn to keep the glider from flying away.
NOTE: All left-right directions are intended for a right-handed thrower. Left handed throwers
should reverse all directions for proper launch and glide performance.
Pick a calm time of the day with no thermal activity and no wind for your first trim flight. Trying to
trim your glider in any kind of wind will make it difficult to tell exactly what your glider is doing and
what it needs to fly correctly. Mornings and evenings are typically the best time for trimming out
your glider.
Choose an open area for your test glides - a park or very large yard is ideal. Hold the fuselage
between your thumb and forefinger, near the CG, just as if your were throwing a paper airplane.
Aim at a point on the ground about 50 feet away and, with the wings level, gently toss your glider.
The proper speed is critical here - too fast and the glider will nose up and stall, too slow and it will
drop to the ground without fling at all. Toss your glider several times until you get the speed right.
Observation is everything - watch your glider carefully to determine what it is doing. Concentrate
on getting a smooth level glide, we’ll worry about turns later. When you see a problem, toss the
glider several more times to verify that you are not causing the problem by an improper throw,
then refer to the following corrections:
If the model repeatedly noses down without climbing first: Double check the CG again. If
the CG is correct, the glider will need a little “up elevator” - gently breathe on the trailing edge of
the horizontal stabilizer and bend it up slightly, about 1/64 in. at first. The moisture from your
breath softens the wood and makes it more pliable. If necessary, you can wet the wood by simply
licking it with your tongue. Toss the glider several more times to determine if this change helped.
If the model noses up and stalls: Check the CG. Generally, moving the CG forward is the
best correction for stalling. Using “down elevator” may have an adverse effect on the launch later
on. Add small amounts of clay to the nose until a smooth, flat glide is achieved.
Once you have achieved a level glide with no tendency for the model to dive or stall, you should
establish a gentle turn to the left*. Do this by gently twisting the tail boom to raise the left* tip of
the horizontal stabilizer, as viewed from the rear of the glider. Establish a turn about 100 feet in
diameter. As a turn is introduced, the glider may tend to nose down - if so, add a little more “up
elevator”.
First Throw
Grasp the model in your right* hand with your thumb and middle finger on either side of the
fuselage. Rest your index finger on the right* finger rest pocket. If a light breeze is present
always face the model into the wind and throw just to the right* of the oncoming wind. Give a firm
reVerb HLG Page 1 V1.0
© 2010 Stevens AeroModel. All Rights Reserved.

side arm throw up at about a 30-45 degree angle with the model banked away from your body at
45 degrees, almost as if you were skipping a rock at the lake. Observe the model’s behavior.
Ideally, the model should climb briskly from the release point then, after gaining approximately 50
ft. of altitude, roll left* and transition into a flat left* turn glide pattern of about 100’ in diameter.
Experiment with your throwing. In many cases, problems with the models transition and altitude
gain can be attributed to your throwing technique.
Do’s and Don’ts of Throwing
•Do give the model a powerful throw however, don’t hurt yourself the more you throw the
more your power will develop.
•Do throw the model just to the right* of the oncoming wind.
•Do not aim the model too high. Release the model at or below 45 degrees it will climb
out briskly from there.
•Do bank the model at 45 degrees away from your body when throwing.
•Do be mindful of what is down-wind from you. Always throw from the up-wind portion of
the field.
•Do not continue to throw a model that is out of trim as each crash risks damage to your
model. Always use your throws productively making trim changes as described in the
chart at the back of this manual to perfect your gliders performance.
•Do not tempt Mr. Murphy – law states that if you show up to the field with only one glider
– you’ll loose it! Bring at least two reVerbs each flying session or risk being subject to
“Murphy’s Law”.
•Do bring your son and daughter along they will enjoy throwing and retrieving just as much
as you!
reVerb HLG Page 1 V1.0
© 2010 Stevens AeroModel. All Rights Reserved.

Hand Launch Glider Trim Guide
Points to keep in mind when prior to making trim changes.
•Rudder controls the launch and transition.
•Stabilizer tilt controls the glide circle diameter.
•CG (balance) and Incidence (decalage) work together to control the models pitch or glide
attitude and air speed. Changes to incidence will often require changes to CG.
Incidence has more of an affect on flight performance as the speed increases. Thus
you’ll change the incidence to solve looping during launch or nose diving after transition.
CG changes more subtly affect the aircrafts flying attitude and will often be made to affect
flight speed.
Hand Launch Glider Trim Guide
Points to keep in mind when prior to making trim changes.
•Rudder controls the launch and transition.
•Stabilizer tilt controls the glide circle diameter.
•CG (balance) and Incidence (decalage) work together to control the models pitch or glide
attitude and air speed. Changes to incidence will often require changes to CG.
Incidence has more of an affect on flight performance as the speed increases. Thus
you’ll change the incidence to solve looping during launch or nose diving after transition.
CG changes more subtly affect the aircrafts flying attitude and will often be made to affect
flight speed.
Hand Launch Glider Trim Guide
Points to keep in mind when prior to making trim changes.
•Rudder controls the launch and transition.
•Stabilizer tilt controls the glide circle diameter.
•CG (balance) and Incidence (decalage) work together to control the models pitch or glide
attitude and air speed. Changes to incidence will often require changes to CG.
Incidence has more of an affect on flight performance as the speed increases. Thus
you’ll change the incidence to solve looping during launch or nose diving after transition.
CG changes more subtly affect the aircrafts flying attitude and will often be made to affect
flight speed.
Problem
Cause
Solution
Model loops on full power
launch and stalls often in glide.
Too much incidence
Decrease incidence by reducing
“up elevator”.
Model pitches up steeply at
launch then nose dives into
ground.
Too little incidence
Increase incidence by adding
“up elevator”.
Model launches high with good
transition but stalls often in
glide.
CG too far back
Add nose-weight until stall
disappears.
Model launches high with good
transition but is fast in the glide
and slightly pitched-down.
CG too far forward
Remove nose-weight until
slower glide is obtained.
Model glides nicely from level
toss. Launches are high but
model fails to consistently roll
left* into transition.
Not enough left* rudder.
Increase left* rudder by bending
the trailing edge of the fin left
until left* roll out is obtained at
transition.
Model rolls sharply to left on
launch additionally, model does
not launch high.
To much left* rudder.
Decrease left rudder by bending
the trailing edge of the fin right*
until launch is high and followed
by a “flip” or roll-out transition to
the left*
Model launches high and
transitions well but glide circle is
tight (less than 100’ in
diameter).
Too much stabilizer tilt.
Carefully, twist boom and
decrease stab tilt until the glide
circle decreases to about 100’ in
diameter.
Model launches high and
transitions well but glide circle is
wide (greater than 100’ in
diameter).
Too little stabilizer tilt.
Carefully, twist boom and
increase stab tilt until the glide
circle increases to about 100’ in
diameter.
Model launches high and
transitions well but glide
tightens up into a tight
descending spiral.
Not enough wash-in
Check model for warps and
wing misalignment. Add
additional wash-in until spiral is
reduced.
*Applies to right-handed throwers. Left-handed throwers will typically trim for the opposite direction.
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© 2010 Stevens AeroModel. All Rights Reserved.